How to Sign a Document Online: Diia, CZO, and Vchasno Compared for Entrepreneurs

To sign a contract, delivery note, or acceptance certificate online, first agree on the final text, check the signatories’ authority, and decide which signing method is acceptable. For a simple exchange of files, you can use the services of the Central Certification Authority (CZO), Diia, or “Vchasno.Sign.” For regular exchanges that require approvals and status tracking, use “Vchasno.EDO.” After signing, download the electronic original with all signatures, verify it, and keep a backup copy.

The rules below apply to document workflows under Ukrainian law. A qualified electronic signature (QES) has the legal effect of a handwritten signature, but it does not replace checking the contract’s contents, a representative’s authority, or any required notarization. Choose the signing method for the specific document and agree on it with the other party.

What kind of electronic signature does a document need?

Ukrainian Law No. 851-IV “On Electronic Documents and Electronic Document Flow” sets requirements for electronic documents, their originals, transmission, and storage. Another law, No. 2155-VIII “On Electronic Identification and Electronic Trust Services”, governs signature types, verification, and trust services. Simply uploading a file to a service does not determine its legal status.

These distinctions are set out in Articles 1, 15, 17-1, and 18 of Law No. 2155-VIII. In particular, Article 15 associates the use of a QES with a high level of trust in electronic identification means, and an AdES based on a qualified certificate with a medium level. A service button labeled “QES” or the presence of a key file does not, by itself, prove that the result is a qualified signature. Check the certificate details and the verification result.

“Electronic digital signature” (EDS) is a term you may still see in interfaces and search queries. When choosing a signing method, check the actual signature type under Law No. 2155-VIII.

Is a QES required for every contract?

There is no general requirement for entrepreneurs to sign every contract with a QES. Article 207 of the Civil Code of Ukraine allows written form using electronic documents and sets conditions for using an electronic signature and equivalents of a handwritten signature. Article 639 of the Code also recognizes the form agreed by the parties.

In e-commerce, Article 12 of Ukrainian Law No. 675-VIII “On Electronic Commerce” provides for an electronic signature under Laws No. 851-IV and No. 2155-VIII, provided all parties to the transaction use an electronic signature device; a signature using a one-time identifier; or an equivalent of a handwritten signature under the parties’ written agreement, which must include samples of those equivalents. A confirmation code for an order can therefore be part of a properly organized procedure, but an arbitrary code or a message saying “approved” should not automatically be treated as a sufficient signature for every document.

Practical recommendation: For regular exchanges of contracts, acceptance certificates, and delivery notes, agree in the contract on the signature type, service or exchange channel, file format, procedure for confirming receipt, and process for making corrections. If the parties have agreed to use a QES, follow that condition. An agreement between the parties does not override a mandatory procedure for a document subject to special legal requirements.

When is ordinary online signing not enough?

Under Part 6 of Article 17 of Law No. 2155-VIII, transactions that by law require notarization and/or state registration may be completed electronically only using qualified electronic trust services. The notarization or registration procedure established by law must also be followed. Uploading a contract to a website and applying a QES does not replace that procedure. If the parties themselves have agreed to notarization, also consider Part 4 of Article 639 of the Civil Code of Ukraine.

Article 8 of Law No. 851-IV separately limits the use of an electronic document as the original of an inheritance certificate or of a document that may exist in only one original copy (except in the legally prescribed case involving a centralized repository). It also limits such use in other cases established by law. Before signing a document that is unusual for your business, check the specific requirements for that document type.

What counts as an original: PDF, scan, signature, or seal?

Under Articles 5 and 7 of Law No. 851-IV, an electronic original must contain the required details, including the relevant electronic signature, and make it possible to prove its integrity and authenticity. The PDF format alone does not do this. If a proper electronic original is stored on several media, each electronic copy is considered an original.

An image of a handwritten signature or seal impression in a PDF is not a cryptographic signature. At the same time, that image does not generally prohibit applying an electronic signature to the file. You need to understand exactly what the person is signing: an electronic document, an electronic copy of a paper document, or confirmation of certain information. A signed scan does not automatically become the electronic original of the original paper document. Its status depends on the document type, the file’s origin, and whether the proper procedure for creating or certifying a copy was followed.

Article 8 of Law No. 851-IV prohibits denying a document legal effect or admissibility as evidence solely because it is electronic. However, the parties still need to establish its authorship, required details, and contents. A printout also does not retain the cryptographic verification capability of the electronic copy.

An electronic seal serves a different purpose from a personal signature. It confirms the origin and integrity of data; a qualified electronic seal carries the relevant presumptions under Part 7 of Article 18 of Law No. 2155-VIII. If a contract requires an expression of intent by an authorized individual, a seal alone does not replace that expression of intent unless the law provides otherwise. A graphic stamp saying “signed with QES” does not replace verification of the electronic signature either.

Comparing services for signing documents online

Choose a service based on how you will send a document to the other party and receive the final copy. Signing an individual file and managing full electronic document flow (EDF) require different workflows.

You can review CZO’s capabilities on its signing and verification pages. Other services describe their procedures in the Diia portal instructions and Vchasno instructions.

Practical recommendation: Before choosing a service, complete an end-to-end exchange with a test file that contains no commercial or personal information. Have both parties sign it, download the result, and verify the signatures using a separate tool. This will show whether the formats are compatible and whether you can save the document outside the service workspace.

Using Diia: two different methods

To sign with a key file, follow the portal instructions: sign in, open “Document signing,” click “Sign a document,” select your key from the storage device, and enter the password. Then select the document, sign it, and save the resulting file. Selecting the key and selecting the document are separate steps, so check carefully which file you open.

Diia.Signature uses a different procedure. According to Diia’s official instructions, you need a smartphone with Near Field Communication (NFC) and a biometric identity document: a card-format passport, biometric international passport, or residence permit. In the app, open “Menu → Diia.Signature → Activate signature,” scan the document code, read it using NFC, complete PhotoID face verification, and create a six-digit personal identification number (PIN). Diia also requires your taxpayer registration number to be in the Unified State Demographic Register.

After this activation, you do not need to complete photo verification every time you sign: you use the PIN. To sign a specific document, select Diia.Signature in a service that supports it and follow the prompts. Do not share your PIN with an employee or counterparty.

Choosing between “Vchasno.Sign” and “Vchasno.EDO”

In “Vchasno.Sign,” upload the final file, select an available signing method, and confirm the action. If other participants need to sign, send them a link as directed by the service instructions. Once all parties have signed, download the completed result.

In “Vchasno.EDO,” first upload the document to the workspace, specify the recipient, add signatories, and set their signing order if needed. Then sign the document and send it to your counterparty. For a store with regular deliveries, it is useful to assign one employee to check quantities and prices and separately designate the person authorized to sign the document. The “Signed by all” status helps track completion of the exchange, but you should still download the final file to your own archive.

How to sign a contract or delivery note: step-by-step

1. Check the parties and their authority. Compare the counterparty’s details with the contract. If a representative is signing for a legal entity, check the basis for their authority: the constituent documents, power of attorney, law, or other appropriate document. Part 2 of Article 207 of the Civil Code of Ukraine expressly requires the signature of an authorized person.
2. Agree on the exchange procedure. Decide on the signature type, result format, signing order, exchange addresses or workspaces, and method for confirming receipt. Make sure the document does not require special certification or registration.
3. Prepare the final file. Check the parties’ names, date, number, goods, quantities, prices, totals, payment terms, and attachments. Remove comments and unfinished edits. Open the exact file you will upload for signing.
4. Select your key and check its details. Make sure the signature belongs to the right person, the certificate is fit for use, and the signing method meets the document’s requirements. If the service workspace requires a key with specific business details, check that technical requirement too.
5. Review the document and sign it yourself. An employee can prepare the file and approval route, but the signatory must review the contents and personally confirm the signature using their own key.
6. Download the complete result. If the service creates a container with the document and signatures, save it. If the signature is detached, save the signature file—for example, with a .p7s extension—and the exact source file. The .p7s extension alone does not guarantee that the document’s contents are inside: that depends on the format used.
7. Obtain the other party’s signature and confirmation of receipt. Send the signed set or link using the agreed procedure. The other party must add their signature to the agreed document, taking any existing signatures into account. Once signing is complete, download the final set.
8. Verify the signatures using the appropriate method. For an AdES or QES, use the CZO’s official verification page. For a detached signature, also provide the source file if the form requires it. Save the verification result with the document. If the parties have lawfully used another signature type, such as a one-time identifier, this form does not replace verification of the relevant procedure: preserve the signed contents and evidence of who confirmed signing and how.
9. File the set in your archive. Save the electronic original, all signatures, delivery and receipt confirmations, the verification result, and documents establishing the representative’s authority. Make a backup copy with access restricted.

Confirmation of receipt must be arranged separately from sending. Under Article 11 of Law No. 851-IV, unless the law or the parties’ prior agreement provides otherwise, a document is considered received once the author receives the recipient’s message confirming receipt. If no procedure has been agreed, the confirmation must state the fact and time of receipt and identify who sent it. So decide in advance which service status or message the parties will accept as confirmation.

How to verify a signature and a signatory’s authority

You need two separate checks: a technical signature check and a check of the person’s authority. Successful cryptographic verification does not prove that an employee is authorized to enter into this particular contract on behalf of the business.

What to check in the file

• Each signatory’s identity. Compare the certificate details with the person who was supposed to sign the document.
• Integrity of the signed data. Verification must confirm that the signature matches these exact contents. If a change is reported, ask for the complete set again without converting the files.
• Signature type and certificate status. Check whether the QES is confirmed if required, and whether the certificate was valid when the signature was created. Account for blocking, revocation, and usage restrictions.
• The provider and trust service. Compare the details with the CZO Trusted List. The status of the specific qualified service matters, not just a familiar company name.
• Time and evidence of its accuracy. Check whether there is a qualified electronic time stamp and its verification result. A time shown in a service event log does not, by itself, mean that such a time stamp exists.

Article 18 of Law No. 2155-VIII sets out the requirements for validating a QES. Part 6 of that article gives a QES the legal effect of a handwritten signature and a presumption of equivalence to it. Article 26 provides that a qualified electronic time stamp carries a presumption of accuracy of the date and time and integrity of the associated data; its use is mandatory for the permanent storage of electronic data.

Check the provider’s qualified status and its services against the Trusted List. The website where you upload a document and initiate signing may use services from a separate qualified provider. A document exchange platform does not itself need qualified status simply because it provides a user interface. Find out who provides the trust service you need.

What to check about authority

Make sure the signatory can represent the relevant party, sign this type of document, and act within any applicable limits. If they act under a power of attorney, check its term, scope of authority, and details. A personal signature, including Diia.Signature, identifies the person; their right to act for the company must be established separately. There is no general requirement to additionally sign every such document with the company director’s QES to confirm representation: what is needed is a proper basis for the signatory’s authority.

Hypothetical example. A supplier sends a store a contract signed by a sales manager. Verification confirms the file’s integrity and the manager’s valid signature. Before signing, the store owner asks for a document authorizing the manager to enter into contracts of this type. If the manager’s authority is not confirmed, the parties involve an appropriately authorized representative and complete signing under the agreed procedure.

What if the certificate has expired?

A certificate expiring today does not automatically invalidate every signature created earlier. Article 18 of Law No. 2155-VIII ties signature validation, among other things, to the certificate’s validity at the time the signature was created. For an old document, you need to be able to establish that time, check the certificate’s status then, and verify the data’s integrity.

Practical recommendation: Verify the document immediately after signing is complete and keep the available verification evidence, time stamps, and related information. For documents with long retention periods, check the availability of the specialized trust service for preservation under Article 28 of Law No. 2155-VIII. If verification cannot establish the validity of an old signature, send the complete set to the provider to find out why.

How to protect your key and confidential documents

Article 12 of Law No. 2155-VIII requires users to keep their private key confidential and prevent other people from accessing it. Do not give your key file, password, or PIN to an accountant, salesperson, or technical specialist so they can sign in your name. If another person needs to sign documents, arrange their own signature and establish their authority properly.

• Sign using a computer or smartphone you control. Before entering your password, check the exact address of the official service.
• Do not share your private key to verify a counterparty’s signature: verification checks the received document and its signature.
• Before uploading a confidential document, read the specific service’s terms on file processing, access, and storage. A public verification form does not make the document public, and it does not remove the need to protect its contents.
• Check format compatibility using a test file. Do not upload sensitive documents to unfamiliar sites for trial signing or verification.
• If you suspect someone else has accessed your key, stop using it and promptly notify the provider so the certificate can be blocked or revoked through the proper procedure.

Where your key is stored depends on the signing method: it may be on a file storage device, a protected device, or a qualified provider’s infrastructure. Articles 18 and 19 of Law No. 2155-VIII also provide for remote use of signature devices. Check the key handling terms for the service you choose.

How to store signed electronic documents

Article 13 of Law No. 851-IV requires electronic documents to be stored in a form that makes it possible to verify their integrity, restore the original format, and continue using the information. Where available, also retain data on the document’s origin and destination and the date and time it was sent or received. The retention period must be no shorter than the one set for the corresponding paper document.

For documents related to taxation, also apply Article 44 of the Tax Code of Ukraine. Paragraph 44.3 sets different minimum periods: for example, 1,825 days for certain documents specified there for legal entities, and 1,095 days for other documents that do not fall into categories with longer periods. The period is generally tied to the filing of the tax return for which the documents were used, not simply to the date they were signed. Account for extensions under Paragraph 44.3 and retention of documents related to an audit or dispute under Paragraph 44.4.

Practical recommendation: Create a separate folder for each agreement or delivery containing the final signed set, verification result, and confirmation of receipt. Keep a register listing the document, counterparty, number, date, and retention period. Store a backup separately and periodically check that files open and signatures still verify. For a detached signature, copy both files together.

After signing, do not overwrite the source file, rescan it instead of retaining the original, or keep only a printout. If you find an error, prepare a correction or a new document under the agreed procedure while preserving the link to the previous version. Before changing services, download the archive and check that you have complete electronic originals.

Preparing a delivery note in Torgsoft for electronic signing

In Torgsoft, you can prepare a document file based on sales data. According to the official instructions for the “Sales” form, “Print → Delivery note” opens an outgoing delivery note that you can save in various formats or print. “Print invoice” opens an invoice with the same output options. For signing externally, choose an available format accepted by both the service you have chosen and the counterparty.

Recommended workflow: check the goods, quantities, prices, and document details in Torgsoft; save the final file; and open it for review. Then sign it separately in the external service you have chosen, obtain the required signatures, and download the complete result. In this workflow, preparing a document in accounting software and applying an electronic signature are separate actions.

Torgsoft’s instructions also describe a “Document files” button in the sales settings for attaching, viewing, and copying files. You can use it to link a sale to the signed set and verification result. Arrange separate backup storage for electronic originals; attaching a file does not perform cryptographic verification.

Official requirements and instructions for getting started

• Ukrainian Law “On Electronic Documents and Electronic Document Flow” dated 22 May 2003, No. 851-IV: Articles 5–8 on documents, signatures, originals, and copies; Articles 10–13 on transmission, receipt, verification, and storage.
• Ukrainian Law “On Electronic Identification and Electronic Trust Services” dated 5 October 2017, No. 2155-VIII: Articles 12, 15, 17–19, 24–26, 28, and 35 on key protection, signature types, verification, certificates, time, and the Trusted List.
• Civil Code of Ukraine dated 16 January 2003, No. 435-IV, Articles 207 and 639 on written form, a signatory’s authority, and the form of contract agreed by the parties.
• Law of Ukraine “On Electronic Commerce” dated 3 September 2015, No. 675-VIII, Articles 11 and 12 on entering into electronic contracts and methods of signing them.
• Tax Code of Ukraine dated 2 December 2010, No. 2755-VI, paragraphs 44.3–44.4 — minimum document-retention periods, when they begin and extensions, and retention until an audit ends and the statutory period for appealing decisions expires and/or the case is resolved in court.
• Signing on the CZO website, signature verification, and the Trusted List.
• Signing a document on the Diia portal and activating Diia.Signature using NFC and signing with a PIN.
• Vchasno instructions: signing a single document, exchanging documents in the workspace, and signing through a link.