Short answer: yes, in the European Union, the United States, the United Kingdom and most of the world, an electronic signature can form a legally binding agreement. The longer answer, the one that actually protects you, is that "electronic signature" covers several very different things, from a typed name at the bottom of a PDF to a certificate-based cryptographic signature, and the law treats them differently. This guide explains the two frameworks you will hear about most, eIDAS in the EU and the ESIGN Act in the US, in plain language, and tells you when a simple signature on a PDF is enough. It is general information, not legal advice: for high-stakes documents, ask a lawyer in your jurisdiction.
The EU framework: eIDAS and its three levels
In the EU, electronic signatures are governed by the eIDAS Regulation (No 910/2014, extended by the eIDAS 2.0 update). Its most important rule is the principle of non-discrimination: a signature cannot be denied legal effect solely because it is electronic. eIDAS then defines three levels of signature.
SES: Simple Electronic Signature
Any data in electronic form attached to other data and used by the signatory to sign. A typed name, a drawn signature on a touchscreen, a signature image placed on a PDF, a checked "I agree" box: all of these are SES. They are legally admissible, and in day-to-day business they are by far the most common form. Their weakness is evidential: if someone disputes the signature, you need surrounding evidence (emails, timestamps, the exchange history) to show who signed and that the document was not altered.
AES: Advanced Electronic Signature
An AES must be uniquely linked to the signatory, capable of identifying them, created with means under their sole control, and linked to the document so that any later change is detectable. In practice this means certificate-based digital signatures. AES carries significantly more evidential weight: tampering breaks the signature visibly.
QES: Qualified Electronic Signature
An AES created with a qualified signature creation device and backed by a qualified certificate from an EU-supervised trust service provider. QES is the only level that eIDAS declares legally equivalent to a handwritten signature across all member states, and the burden of proof reverses: it is on the person disputing the signature.
The US framework: ESIGN and UETA
The United States takes a simpler approach. The federal ESIGN Act (2000) and the state-level UETA provide that a signature, contract or record may not be denied legal effect solely because it is in electronic form. There are no tiers like eIDAS: what matters is intent to sign, consent to do business electronically, association of the signature with the record, and record retention. A drawn or typed signature on a PDF, combined with a clear email trail, satisfies these requirements for the vast majority of business documents. Courts have upheld e-signed agreements for decades.
When is a simple signature enough?
For most everyday documents, an SES-level signature on a PDF is both legal and customary:
- Commercial contracts and engagement letters between businesses
- NDAs and confidentiality agreements
- Quotes, proposals and purchase approvals
- Invoices and internal sign-offs
- Freelance agreements, timesheets, HR acknowledgments
- Rental applications and many lease agreements (jurisdiction-dependent)
Some categories typically require a qualified signature, a notary, or plain paper, depending on the country: real-estate transfers, wills and inheritance documents, marriage and family-law acts, certain court filings, and some consumer-credit agreements. If your document falls into one of these, check the specific national requirement before signing anything electronically.
What this means for signing PDFs in practice
When you sign a PDF with a drawn or uploaded signature, for example with the EasyPDF sign tool, you are producing a simple electronic signature. That is exactly what most contracts need. To maximize its evidential strength:
- Keep the exchange trail. Send and receive the document by email, and keep those emails. They anchor identity, date and intent.
- Sign the final version. Any edit made after signing undermines the signature's credibility, and breaks cryptographic signatures outright.
- Add the date and place next to the signature block, as you would on paper.
- Distribute the signed copy to every party and archive your own copy unmodified.
- Escalate the signature level to the stakes. For a document worth litigating over, consider an AES or QES through a qualified trust provider instead of a simple signature.
Frequently asked questions
Can a scanned image of my handwritten signature make a contract valid?
Often yes, it counts as a simple electronic signature, and contracts rarely fail for form alone. But it is the weakest variant in evidential terms because the image can be copied. Pair it with a solid email trail, or use a stronger signature method for important documents.
Is an electronic signature valid internationally?
Most jurisdictions recognize electronic signatures (EU, UK, US, Canada, Australia, and many others under UNCITRAL-inspired laws). Cross-border enforceability depends on the governing law chosen in the contract, so check the requirements of that jurisdiction.
Does signing a PDF electronically prevent later modification?
A simple signature does not technically lock the file. A certificate-based (AES/QES) signature makes any later change detectable. In both cases, keep the version you signed; comparing documents later can prove alteration.
Do both parties need to use the same signing tool?
No. There is no legal requirement for a shared platform. Each party can sign with a different tool as long as intent and integrity can be shown.