An electronic signature is any electronic mark you adopt with the intent to sign, and federal law says it cannot be refused legal effect just because it is electronic.[1][2] A digital signature is a cryptographic seal, usually backed by a certificate, that proves who signed and that the file has not changed since.[5] A typed or drawn signature on a PDF is the first kind, not the second.
01Electronic signatures: a legal category
The federal ESIGN Act defines the term broadly: “The term “electronic signature” means an electronic sound, symbol, or process, attached to or logically associated with a contract or other record and executed or adopted by a person with the intent to sign the record.”[2] A typed name, a drawn squiggle, a click on an “I agree” button and a recorded “yes” can all qualify. What makes it a signature is the intent.
The core rule is about not discriminating against the format. For transactions in or affecting interstate or foreign commerce, “a contract relating to such transaction may not be denied legal effect, validity, or enforceability solely because an electronic signature or electronic record was used in its formation.”[1] It does not force anyone to accept electronic signatures; it stops a signature being rejected only because it is electronic.
States have their own version. ESIGN lets a state law modify its rules only if that law “constitutes an enactment or adoption of the Uniform Electronic Transactions Act as approved and recommended for enactment in all the States by the National Conference of Commissioners on Uniform State Laws in 1999”, or meets the other conditions in the section.[4] That uniform act is UETA.
02Where ESIGN does not apply
Section 7003 carves out several kinds of documents, including:[3]
- “a statute, regulation, or other rule of law governing the creation and execution of wills, codicils, or testamentary trusts;”
- “a State statute, regulation, or other rule of law governing adoption, divorce, or other matters of family law;”
- “court orders or notices, or official court documents (including briefs, pleadings, and other writings) required to be executed in connection with court proceedings;”
- notices of “the cancellation or termination of utility services (including water, heat, and power);”
Agencies can also set their own rules for what they accept. USCIS is the clearest example: it accepts a “Signature captured electronically through a USCIS online account when prompted during online filing” but not a “Signature created by a typewriter, word processor, software program, stamp, auto-pen, or similar device”.[6] The IRS, for requesters who collect W-9s electronically, requires “an electronic signature by the payee whose name is on Form W-9 that authenticates and verifies the submission”.[7]
The law says an electronic signature can count. The person or agency receiving it still decides which kinds they accept, within that law.
Our reading of [1]
03Digital signatures: cryptography
NIST defines a digital signature as “The result of a cryptographic transformation of data that, when properly implemented, provides a mechanism for verifying origin authentication, data integrity, and signatory non-repudiation.”[5] In a PDF, that means the signer’s software computes a fingerprint of the file and seals it with a private key; a certificate ties the key to a person or organization. If one byte of the signed content changes later, viewers report the signature as invalid.
| Simple electronic signature | Certificate-based digital signature | |
|---|---|---|
| What it is | A mark adopted with intent to sign[2] | A cryptographic transformation of the data[5] |
| Shows who signed | By context (email, account, witness) | By certificate |
| Detects later changes | No | Yes, viewers flag an altered file |
| Typical use | Contracts, forms, W-9s sent to a requester | Regulated workflows, documents that must prove integrity |
04What pdfnex offers
Sign PDF places a simple electronic signature (drawn, typed or uploaded) on the page, in your browser. It does not create certificate-based digital signatures, and we say so on the tool. Whether a simple signature is enough is up to whoever receives the document; for USCIS filings it is not, so sign those by hand.
This guide quotes federal statutes and agency guidance. It is not legal advice.