Sign a PDF

What this is, stated plainly

This draws a picture of your signature onto the page. It is the digital equivalent of ink on paper: visible, unmistakable, and exactly as verifiable as a signature on a printed contract — which is to say, by eye.

It is not a cryptographic digital signature. It does not embed a certificate, it does not prove who applied it, and it will not show a green tick in Acrobat's signature panel. Anybody can copy the image out and put it on another document.

We are saying this at the top because it is the thing most sites in this category are vague about, and the vagueness matters: an electronic signature's legal effect turns on the surrounding process — consent, identification, an audit trail — rather than on how the mark was made. A drawn signature is widely accepted for ordinary agreements in most jurisdictions and is not the right instrument for something that specifically requires a qualified or certified signature. If a document tells you it needs one, this is not it.

Placing it where you mean

Position is measured in points from the left edge and from the top of the page, the way you would read a ruler, at 72 points to the inch. On A4 that is 595 points wide and 842 tall; on US Letter, 612 by 792.

Pages that are marked as rotated are handled properly, and that is less common than it should be. A PDF can carry a rotation flag so it displays turned while its underlying coordinates stay put — and a tool that ignores it puts your signature in a different corner, on its side. Here the position is measured on the page as you see it, and it is checked at every rotation on every build.

Photograph your signature, do not scan it

Sign a plain white sheet with a dark pen, photograph it square-on in good light, and crop close. Then leave "drop the white background" on: the paper becomes transparent so the signature sits on the document rather than in a white box that covers whatever it lands on.

That transparency is done by turning brightness into opacity rather than by cutting at a threshold. The difference is visible — a hard cut leaves every stroke with a jagged white fringe, which is what makes a pasted signature look pasted. Keeping the stroke's own soft edge is what makes it read as ink.

Or just type it

Leave the image out and type a name instead, and it is drawn in an italic face. It is honest about what it is — nobody mistakes a typed name for a handwritten one — and for a great many internal documents that is entirely sufficient. Ticking the date option adds today's date underneath in small print.

If the PDF is also a form

Fill it in first with the form filler, then sign the result. If you have a filled form that has not been flattened, turn on the flatten option here and the field values are baked into the page at the same time as the signature — which stops both from being edited afterwards.

Your document is not kept

The work happens on our server because it needs the PDF libraries, in a directory of its own, and the file is deleted as soon as your download has been sent. Given what people sign, that matters: tenancy agreements, employment contracts, medical consent forms.