Is a digital PDF signature legally valid?

1 min read·25 July 2026

Adding a signature to a PDF takes seconds — but is it legally binding? The answer depends on the type of document and the type of signature. Here is the short guide.

Simple electronic signature (SES)

An image of your signature on a PDF is a "simple electronic signature" (SES). This is legally valid for most informal and business contracts. EU law (eIDAS) recognises SES as valid evidence of agreement.

When is SES enough?

For most agreements between parties (purchase agreements, freelance contracts, order confirmations) a simple digital signature is legally sufficient. The combination of the signed PDF plus email communication provides strong evidence.

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When is more required?

Official documents (notarial deeds, mortgage documents, wills, government forms) sometimes require an advanced or qualified electronic signature (AES/QES) with a recognised certificate. This needs eIDAS-certified trust services.

Strengthening the evidence

To strengthen the evidentiary value of a simple signature: send the signed PDF via traceable email, include a clear date and description in the document itself, and keep the communication trail around the signature.