Sign a PDF

A permission slip, an offer letter, a lease renewal, a consent form from a clinic. The old workflow was print, sign, scan, attach, and the scan was never quite straight. The tool above skips the paper: draw with a finger on a phone or a mouse on a laptop, place the mark on the line, and download a PDF that looks like it was signed in ink. The signature is drawn into the file on your device, and neither the document nor your signature is sent anywhere.

How to sign a PDF

Visible signature or certificate: which one you need

Two different things are called a digital signature, and they answer different questions. A visible signature answers "did this person mark the document?" the way ink does. A certificate signature answers "has this exact file been altered since a verified identity signed it?" using cryptography.

Under most e-signature laws, including the US ESIGN Act and the EU's eIDAS regulation for simple electronic signatures, a visible mark applied with intent to sign is valid for ordinary agreements. Where a stronger form is mandated, the mandate will say so. If you are unsure, the person asking for the signature usually knows which kind they need.

Draw, type or upload

• Draw gives a genuinely handwritten mark, especially on a phone or tablet. On a laptop trackpad it can look shaky; a mouse is better, and a typed signature is a reasonable fallback.
• Type renders your name in a flowing signature typeface. Quick, consistent, and entirely appropriate for internal sign-offs where nobody expects a pen.
• Upload reuses a real signature. Sign a blank sheet with a dark pen, photograph it in good light, and crop tightly. A PNG with a transparent background sits cleanly on the page; a plain photo brings its paper texture along, so remove the background first if you can.

Placing a signature so it looks signed, not pasted

• Size to the line. Drag the corner handle until the signature is about as wide as the printed line, and slightly taller than the surrounding text.
• Leave room for the date. Signature blocks usually pair a line with a date field. Keep the mark clear of it, then type the date in the Editor if the form does not have a field.
• Check every page that needs a mark. Initials on each page, a witness line, a second signature block on the last page. Page through before downloading.
• Do not shrink a signature to fit an initials box. Make a second, shorter signature of your initials instead. It reads better and is what the box expects.

Making the signed file harder to tamper with

The signature is drawn into the page, which is the same category of content as the printed text, so a reader cannot switch it off. Someone with a full PDF editor could still move it or remove it. Two steps raise the bar when that matters.

• Flatten and fuse. Run the signed file through Compress in Strong mode. Each page becomes a single image with the signature fused into the pixels, at the cost of selectable text. Do this on the copy you send, and keep the original.
• Lock it. Password protect the signed copy with editing turned off, and share the password by a separate channel. The permission flag deters casual changes; the password prevents the file being opened by anyone else.
• Keep your own copy. A signed PDF in your possession, with the email it went out in, is the evidence that matters in a dispute. The other party's copy is theirs.

Why your signature should never be uploaded

A signature is a piece of identity, and the documents it goes on are contracts, financial forms and personal records. An online signing tool that receives the document and the signature together has everything needed to reproduce your mark on anything. Even with good intentions, that is a copy of your signature on a server you will never see.