What is an electronic signature?

An electronic signature (e-signature) is a digital mark or action, typing a name, drawing a signature, clicking "I accept", attached to a document to show a specific person agreed to it, in place of a wet-ink signature.

What it means in practice

For most business contracts in the UK, EU and US, an electronic signature is legally binding in the same way a handwritten one is, provided you can show who signed, what they signed, and when. That evidence is the audit trail: a timestamped record of each signer's identity check, IP address, the exact document version they saw, and the order they signed in if there's more than one signer. Without that trail, a signature is just a mark, with it, it's defensible if a client later disputes what they agreed to.

Once every party has signed, the accepted document should be locked as an immutable record. If the scope changes afterwards, that's a new change request or amendment, not an edit to what was already signed.

Example

A client receives a signed-off specification by secure link, reviews it, and signs electronically. The system logs the signing order, timestamps and IP address into an audit certificate, then locks the accepted document as a permanent snapshot, the version both sides can point back to.