What is an electronic signature? Guide 2026

Definition and context

An electronic signature is a technical process that allows a person to express their consent on a digital document, with the same value as a handwritten signature on paper. It is not limited to the image of a scribble pasted onto a PDF: behind the signature lies a cryptographic mechanism that binds the signer to the document and guarantees its integrity.

The reference framework in Europe is the eIDAS regulation (No. 910/2014), which defines three levels: simple, advanced, qualified. Each level corresponds to different requirements regarding the identification of the signer and the strength of the proof.

Why electronic signature has become essential

Businesses today process dozens of contractual documents per week: employment contracts, quotations, purchase orders, mandates, leases, NDAs… Having these documents circulate in paper form is costly in terms of time and logistics.

A few figures often cited in the industry:

• a paper contract takes between 2 and 5 days to return signed on average;

• the same operation with electronic signature takes a few minutes to a few hours;

• the complete cost of a paper cycle (printing, postage, filing, follow-up) is around €15 to €35 per document.

Beyond the figures, electronic signature provides superior traceability: each step is time-stamped, each action of the signer is recorded, the IP address is captured. Paper, on the other hand, leaves only a scribble.

How does an electronic signature work?

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

• The sender deposits a document (most often a PDF) on a signature platform.

• They add the recipients (signers), place the signature fields and define the order.

• Each signer receives a secure email link. They open the document, authentication is verified (OTP by SMS for the advanced level for example), they click to sign.

• The platform calculates a cryptographic fingerprint of the document, associates it with the signer's identity and a time stamp, and integrates everything into the final PDF.

• The signed PDF now carries an audit trail: time-stamped log of all actions, IP address, user-agent, OTP confirmation.

To learn more about the mechanics, see how an electronic signature works.

The three eIDAS levels

European regulation distinguishes three levels of electronic signature. Best practice is to choose the level appropriate to the document's stakes, not to systematically take the strongest one (more demanding = more costly friction for the signer).

• Simple (SES): a simple click or a tick box is sufficient. Suitable for low-stakes documents: quotations, purchase orders, internal agreements.

• Advanced (AES): identification of the signer by a second factor (OTP SMS + email typically). Unique link between the signer and the document. Suitable for employment contracts, leases, mandates.

• Qualified (QES): qualified certificate issued by an approved Trust Service Provider (QTSP). Equivalent in law to a handwritten signature throughout the EU. Reserved for authentic acts or highly formal documents.

For the complete distinction with examples, see simple, advanced, qualified: what are the differences.

Documents that can be signed electronically

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

• employment contracts (permanent, fixed-term, apprenticeship)

• quotations, purchase orders, proforma invoices

• confidentiality agreements (NDA)

• sales mandates, management mandates

• residential and commercial leases

• inter-company agreements, protocols of agreement

• amendments, powers of attorney, certificates

Some acts remain excluded or subject to conditions (notarised acts, civil status records, certain judicial procedures): check the framework applicable to your document before launching a signature with strong evidential value.

How Certyneo helps you

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

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

Discover the Certyneo electronic signature solution

FAQ

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

Yes, provided that the signature level is appropriate to the document and that the identification of the signer 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 evidence solely on the ground that it is electronic.

Which signature level should I choose?

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

Is electronic signature free?

Some platforms offer a free plan for a few signatures per month. Beyond that, the tool becomes paid. 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 touchscreen.

What happens in case of dispute?

The platform provides on request the complete audit trail: time stamp, IP address, authentication, cryptographic fingerprint. This reusable evidence is accepted by French and European courts as long as it complies with eIDAS.

Conclusion

Electronic signature is no longer a gadget: it is a productivity tool that divides the signature cycle by 10, reduces administrative costs and provides superior traceability compared to paper. Start with low-stakes documents to familiarise yourself, then gradually extend to all your processes.

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