Electronic signatures have had legal effect in most of the world for over twenty years. The United States (ESIGN and UETA), the European Union (eIDAS), the United Kingdom, Canada, Australia and dozens of other countries all say broadly the same thing: a signature is not invalid merely because it is electronic. The interesting questions are what makes a particular electronic signature reliable enough to rely on, and where the exceptions are.
The three tiers most laws recognise
- Simple electronic signature — any electronic mark intended as a signature: a typed name, a drawn signature, a click on "I agree". Valid for most contracts.
- Advanced electronic signature — uniquely linked to the signer, capable of identifying them, created under their sole control, and linked to the document so that later changes are detectable.
- Qualified electronic signature — an advanced signature backed by a certificate from an accredited provider. In the EU it is legally equivalent to a handwritten signature; elsewhere the concept exists under different names.
For engagement letters, tenancy agreements, NDAs, consent forms, settlement terms and most commercial contracts, a well-evidenced simple or advanced signature is what businesses use every day.
What "well-evidenced" means
Courts do not ask "was it electronic?"; they ask "can you show who signed, what they signed and when?". A signature process that records the signer's identity check (for example, a one-time code sent to their email), a timestamp from a server, the IP address, and a seal that makes any later alteration to the document detectable answers all three. A picture of a signature pasted onto a PDF answers none. We go through the mechanics in what makes a signed PDF legally sound.
The exceptions
Every jurisdiction keeps a short list of documents that still require a wet signature, a witness in the room, a notary or a specific form. The usual suspects: wills and testamentary documents, certain deeds and land transfers, some family-law documents, court filings in some systems, and a few consumer-protection notices. The list differs by country and sometimes by state or region — check before you send anything that touches property, family or succession.
Cross-border signing
A contract signed electronically by parties in two countries is generally valid if it is valid under the law governing the contract. Choose the governing law in the contract and make sure the signature process meets that law's standard. Advanced-level evidence (identity check, timestamp, tamper seal) is accepted almost everywhere and is the sensible default for international work.
Keeping the proof
The signed document is only half of the evidence; the audit certificate — who verified, when, from where — is the other half. Keep them together, with the matter they belong to, for as long as the contract's limitation period runs. A signature you cannot find the audit trail for is a signature you will have to prove some other way.
