Sign X PDF · Guides
Visible signature vs digital signature on a PDF
Many people say “sign a PDF” when they mean placing a handwritten-style mark on a page. That is a visible (electronic appearance) signature. A certificate-backed digital signature is a different technology: it uses cryptography and a digital certificate, not just an image or ink stroke. Sign X PDF provides visible signature placement only.
This page explains product terminology for Sign X PDF. It is not legal advice. Requirements for electronic or digital signatures vary by jurisdiction and use case.
What “sign PDF” often means in everyday use
In common language, signing a PDF usually means adding a mark that looks like a signature: draw with a pointer or stylus, type a name in a signature style, or place a photo of a handwritten signature on a page, then save a new PDF.
That mark can be enough for informal approval workflows where the other party mainly needs a visible sign-off on the document. It is not the same thing as a cryptographic digital signature field that a PDF reader can mathematically verify.
Visible / electronic appearance signatures
A visible signature is content drawn onto or overlaid on the page. Readers see ink-like strokes, typed text, or an image. The PDF still opens as a normal document; the mark is part of the page appearance (or an annotation-like visual), depending on how the tool writes the file.
- Drawn signature from a signature pad
- Typed name styled as a signature
- Uploaded or camera-captured signature image
- No certificate, identity proofing, or cryptographic seal by itself
Certificate-backed digital signatures
A digital signature in the cryptographic sense uses public-key technology. The signer’s certificate is bound to the document bytes so that later changes can invalidate the signature, and compatible viewers can report whether the signature is intact and who the certificate claims to identify.
That workflow typically involves certificate issuance, private keys, and tools that implement standards such as PKCS#7/CMS-style PDF signatures (often discussed alongside PAdES profiles). Sign X PDF does not implement this path.
What Sign X PDF does
Sign X PDF’s browser sign tool is designed for visible signature placement: draw, type, or place an image signature on a PDF in your browser. Processing is intended to stay on your device rather than uploading the PDF to Sign X PDF servers for signing.
Limitations are intentional product boundaries, not temporary omissions in the marketing copy.
- Supported: draw, type, and image-based visible signatures
- Not supported: certificate-backed cryptographic signing
- Not supported: identity verification, KYC, or audit-trail packages
- Not supported: claiming the mark is “legally binding everywhere” or eIDAS/ESIGN-certified by itself
How to choose the right kind of signature
If you only need a visible mark for an informal process (for example, a form your counterpart accepts as a scanned wet-ink substitute), a browser visible-signature tool may be enough.
If you need cryptographic integrity, certificate identity, long-term validation, or regulated e-signature workflows, use a product that explicitly implements digital/certificate signing—and follow your organisation’s policy. This page is product documentation, not legal advice.
FAQ
Is drawing a signature on a PDF a digital signature?
Not in the cryptographic sense. Drawing places a visible mark. A digital signature uses certificates and cryptography so viewers can verify integrity and certificate claims.
Does Sign X PDF create certificate-backed signatures?
No. Sign X PDF places visible signatures (draw, type, or image). It does not apply certificate-based cryptographic PDF signatures or verification.
Is a visible signature legally binding?
Legal effect depends on jurisdiction, the parties’ agreement, and the transaction. Sign X PDF does not give legal advice and does not claim that a visible mark is automatically valid everywhere.
Electronic signature vs digital signature — which phrase does Sign X PDF use?
We prefer “visible signature” or “add a signature” for our product. We avoid calling our marks “digital signatures” when that would imply cryptography.