Guides

AI-Assisted PDF Signing: Auto-Detect Signature Fields and Auto-Fill Forms

Published

What's new: AI does the tedious part of signing

Signing a PDF usually means scrolling through every page hunting for the 'Signature:' and 'Date:' lines, then manually filling in any other blank fields the document asks for. Sign PDF now automates the hunting: it scans the document for likely signature and date spots, suggests values for form fields it can confidently infer from the document itself, and checks that you haven't finalized a document with no signature on it at all.

None of this is a black box that silently changes your document — every suggestion is shown to you first and only applied when you accept it.

Auto-detect where to sign (and where to date it)

As soon as you upload a document, Sign PDF scans the text for common signature-block phrasing — 'Signature:', 'Signed by', 'Authorized Signature' — and date phrasing like 'Date:' or 'Signed on', and marks each spot with a dashed outline directly on the page.

Each suggestion has its own accept or reject button. Accepting a signature spot opens the normal draw/type/upload signature tool already targeted at that exact location; accepting a date spot drops in today's date immediately, no typing required. Reject just dismisses that one suggestion — nothing is placed on the page until you say so.

Let AI fill the rest of the form

If the uploaded PDF has real fillable form fields — not just visual lines, but an actual interactive form, like a registration or intake form — a 'Fill form' button appears. AI reads the document's own text and proposes a value for each field it can confidently infer, grounded strictly in what the document already says, not invented.

Every proposed value shows up in an editable, checked-by-default list — the same review-before-you-act pattern Smart Redact uses for suggested redactions. Uncheck or edit anything before applying; only what you confirm gets written into the form.

Never accidentally send an unsigned document

Clicking Apply & Download with no signature placed now shows a warning instead of silently producing an unsigned file — a real, easy mistake when a document has several fields and it's simple to fill everything except the signature itself.

It's a warning, not a hard block, since a signature genuinely isn't always required (initials-only forms, for instance). You can jump straight back to the detected signature spot, or confirm and proceed anyway if that's actually what the document needs.