What is an electronic signature? Guide 2026

Definition and context

Aelectronic signatureis a technical process which allows a person to express their consent on a digital document, with the same value as a handwritten signature placed on paper. It is not limited to the image of an initial pasted on a PDF: behind the signature, there is a cryptographic mechanism which binds the signatory to the document and guarantees its integrity.

The reference framework in Europe is the regulationeIDAS(n°910/2014), which defines three levels: simple, advanced, qualified. Each level corresponds to different requirements on the identification of the signatory and the strength of the proof.

Why electronic signature has become essential

Companies today process dozens of contractual documents per week: employment contracts, quotes, purchase orders, mandates, leases, NDAs, etc. Circulating these documents in paper form is expensive in terms of time and logistics.

Some orders of magnitude often cited in the profession:

• a paper contract enters2 and 5 daysto return signed on average;
• the same operation in electronic signature takesa few minutes to a few hours;
• the complete cost of a paper cycle (printing, postage, archiving, reminder) is around15 to 35 € per document.

Beyond the numbers, the electronic signature providessuperior traceability: each step is time-stamped, each action of the signer is logged, the IP address is captured. The paper leaves only a scribble.

How does an electronic signature work?

The process always follows the same logic, regardless of the supplier:

1. The issuer submits a document (most often PDF) on a signature platform.
2. It adds the recipients (signatories), places the signature fields and sets the order.
3. Each signatory receives a secure link by email. He opens the document, the authentication is verified (OTP by SMS for the advanced level for example), he clicks to sign.
4. The platform calculates a cryptographic fingerprint of the document, associates it with the identity of the signer and a timestamp, and integrates everything into the final PDF.
5. The signed PDF now includes aaudit trail: timestamped log of all actions, IP address, user-agent, OTP confirmation.

To go further on the mechanics, seehow does an electronic signature work.

The three eIDAS levels

The European regulation distinguishes three levels of electronic signature. Good practice consists of choosing the level adapted to the issue of the document, not systematically taking the strongest (more demanding = more costly in friction for the signatory).

• Single (SES): a simple click or a checkbox is enough. Suitable for low-stakes documents: quotes, purchase orders, internal agreements.
• Advanced (AES): identification of the signatory by a second factor (OTP SMS + email typically). Unique link between the signatory and the document. Suitable for employment contracts, leases, mandates.
• Qualified (QES): qualified certificate issued by an approved trust service provider (QTSP). Legally equivalent to a handwritten signature throughout the EU. Reserved for authentic or very formal acts.

For the full distinction with examples, seesimple, advanced, qualified: what are the differences.

Documents that can be signed electronically

In practice, almost all contractual and commercial documents are now signed electronically:

• employment contracts (CDI, CDD, work-study)
• quotes, purchase orders, proforma invoices
• confidentiality agreements (NDAs)
• sales and management mandates
• residential and commercial leases
• inter-company agreements, memorandums of understanding
• amendments, powers of attorney, certificates

Certain acts remain excluded or subject to conditions (notarial acts, civil status documents, certain legal procedures): check the framework applicable to your document before signing a signature with strong probative value.

How Certyneo helps you

Certyneo is a European electronic signature platform, hosted in the EU, eIDAS and GDPR compliant by design. It covers simple (SES) and advanced (AES) levels with dual-factor authentication (email + OTP SMS via Twilio Verify), and interfaces with qualified service providers for qualified signatures (QES) when the use case requires it.

Each envelope sent via Certyneo automatically generates a signed PDF with audit footer, a time-stamped log kept for 10 years and reusable proof in the event of a dispute.

Discover the Certyneo electronic signature solution

FAQs

Does the electronic signature have the same value as a handwritten signature?

Yes, provided that the level of signature is adapted to the document and that the identification of the signatory as well as the integrity of the document are provable. In Europe, the eIDAS regulation establishes a principle of non-discrimination: a signature cannot be refused as proof simply because it is electronic.

What level of signature to choose?

For the majority of everyday cases (quotes, purchase orders, internal agreements), a simple signature is sufficient. For an employment contract, a lease or a mandate, choose advanced signature. For an act with very strong legal value, explore the qualified signature.

Is electronic signature free?

Some platforms offer a free plan for a few signatures per month. Beyond that, the tool becomes chargeable.See the free/paid comparison.

Can you sign from a smartphone?

Yes, all modern platforms allow signing from a smartphone or tablet. The signer clicks on the link received by email and can sign directly on the touch screen.

What happens in the event of a dispute?

The platform provides the complete audit trail on request: timestamp, IP address, authentication, cryptographic fingerprint. This reusable proof is accepted by French and European courts as long as it is eIDAS compliant.

Conclusion

The electronic signature is no longer a gadget: it is a productivity tool that divides the signature cycle by 10, reduces administrative costs and provides greater traceability than paper. Start with low-stakes documents to get familiar, then gradually expand to all of your processes.

Try Certyneo to send, sign and track your documents online simply, quickly and securely.