DoxlyWhat actually happens when you sign a PDF (and when it isn't legally a signature)
Legal 10 September 2026
This is not legal advice
This explains how electronic signatures are generally treated in the US and EU and where the real distinctions sit. It is not a substitute for asking a lawyer about a specific document, and the exceptions below are exactly the kind of thing worth checking before assuming they don't apply.
Three things get called “signing a PDF,” and they are not the same
Drawing or typing a signature onto a page, which is what most free tools — including the one on this site — actually do. This places an image of a signature into the document. It proves nothing cryptographically about who placed it or whether the document changed afterward; it is the electronic equivalent of the visual mark a wet-ink signature leaves.
A certificate-based digital signature, which uses a cryptographic certificate tied to a verified identity to sign the document's actual contents. This can prove who signed and can detect if the file was altered afterward, because the signature is mathematically bound to the exact bytes of the document at the moment of signing. This is a different, more involved process than drawing a signature, and it generally requires a certificate from a recognized authority.
A wet-ink signature on paper, which is what both of the above exist to replace, and which several categories of document still require by law regardless of how convenient the electronic alternative is.
What actually makes an electronic signature legally valid
In the US, two overlapping laws cover this: the Uniform Electronic Transactions Act (UETA), a model law adopted by nearly every state since 1999, and the federal ESIGN Act, passed in 2000. Between them, an electronic signature — including a drawn one — generally cannot be denied legal effect purely for being electronic, provided four conditions are met: both parties intended to sign, both parties agreed to conduct the transaction electronically, the signature is genuinely associated with the record it applies to, and the signed record can be retained and reproduced.
The EU's equivalent is the eIDAS regulation, which recognizes three tiers rather than a single standard: a simple electronic signature (drawing a signature falls here), an advanced electronic signature, and a Qualified Electronic Signature (QES). Only a QES, which requires a certificate from an officially recognized trust provider, is guaranteed equivalent to a handwritten signature in every EU member state automatically. A simple electronic signature can still hold up, but it is not given that automatic equivalence, and its weight in a dispute depends more on the surrounding evidence.
What still needs a wet-ink signature regardless
Both the US and EU frameworks carve out specific exceptions, and they are fairly consistent across sources: wills and codicils, certain court orders and filings, adoption papers, divorce and family law documents, and some notarized instruments. These exist because the underlying law governing that specific document type predates or was deliberately left outside electronic signature legislation, not because of any technical limitation. If a document falls into one of these categories, an electronic signature of any kind, drawn or certificate-based, is very likely not going to satisfy it.
The practical takeaway
For the overwhelming majority of everyday agreements — contracts, invoices, internal approvals, most business paperwork — a drawn electronic signature is legally sufficient in the US and EU, provided the basic conditions above are met. It is not the same thing as a certificate-based digital signature, and if a counterparty or institution has specifically asked for a digital signature certificate, a drawn signature is not going to satisfy that request — that is a different, stronger guarantee being asked for. And if the document is a will, a court filing, or anything adjacent to family law, check first rather than assume either kind of electronic signature applies.