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How to sign a PDF

The Sign PDF tool adds a drawn, typed or uploaded visual signature without uploading the document or storing the signature. This guide also explains when that is enough, when a certificate signature is required, and why signing should be the last change to the file.

Add signature to PDF

What signing a PDF actually means

Almost everyone asking this question wants a picture of their name on a page. That is an electronic signature, and it is what a free reader gives you in about a minute. It is a drawing sitting on top of the page, no different from any other image in the file.

The other kind is a certificate signature. To sign a document digitally in that sense locks a cryptographic hash of the whole file to your identity, so a reader can say who signed it and whether a single byte changed afterwards. That one takes a certificate, so it is covered separately in the certificate guide.

Sign on a Mac

Preview is already installed and it does this well. Open the PDF, turn on the markup toolbar, and look for the signature control. You can draw with the trackpad or hold a signature written on white paper up to the camera, which gives a much cleaner result than a trackpad ever will.

The signature is saved, so the second document takes seconds. Drag the box onto the page, size it, and save. Apple moves these controls around between releases, so trust the icons in the toolbar rather than a menu path written down a year ago.

Sign on an iPhone or iPad

Markup is built into the Files app and into Mail, so a contract that arrived as an attachment can be signed without moving it anywhere. Open the attachment, open Markup, and add a signature from the same control that adds text and shapes.

A finger works. An Apple Pencil works better. Either way the result is a drawing placed on the page, exactly like the Mac path, and the file you send back is a normal PDF that opens anywhere. Nothing here needs an account or a subscription.

Sign on Windows

Adobe Acrobat Reader is free and its Fill and Sign feature covers this. Draw your name once, place it, save. Microsoft Edge can open and draw on a PDF as well, though its ink is a freehand drawing rather than a stored signature you can reuse.

If you would rather not install anything, the scan route still works: print the page, sign it, photograph it, and turn the photograph into a PDF page with Images to PDF. It is slower and it looks like what it is.

Sign it last

Every other operation you might run rebuilds the document. Merging, reordering, rotating, cropping and compressing all copy pages into a new file, and a certificate signature is bound to the bytes of the old one. Sign after all of that, never before.

A drawn signature is different because it is only page content, so it survives being merged or reordered. Even then the order is worth keeping, because it saves you checking whether the image landed on the right page after the shuffle.

What to do with the signed file

If it has to go by email and the mailbox bounces it, the compress tool takes a size in KB and checks the text is still selectable before it hands the file back. Signature images compress well, because they are pictures.

If it holds anything private, the protect tool puts an open password on it, and the privacy scan lists what the file says about the software and the people who touched it.

When a drawn signature is not enough

Some organisations will not accept a drawing. Tenders, some land and company filings, and some cross-border contracts ask for a signature a machine can verify. If somebody has told you the signature must be verifiable, they mean a certificate.

The comparison guide explains how to tell which one you are being asked for, and the signature guide covers getting a clean image of your handwriting onto the page.

Questions people ask

Can I sign a PDF on this site?
Yes. Sign PDF adds a drawn, typed or uploaded visual signature in this tab. It does not create a certificate signature, signing timestamp or identity proof.
Is a signature I draw with a mouse legally valid?
For most everyday agreements, yes, and it is the sort of signature that ordinary contracts are settled with every day. The answer that matters is what the party asking for it will accept, so ask them.
Do I need to print and scan a document to sign it?
No. Every route in this guide keeps the document digital. Printing and scanning still works if you have no other option, and Images to PDF turns the photograph of the signed sheet back into a page.
Why did my signature disappear after I edited the PDF?
A certificate signature covers the whole file, so any later change breaks it and the reader drops or flags it. Sign after you have finished merging, rotating and compressing, not before.

Do it now

The tool runs in this browser. Your file never leaves the machine, and the result is checked before you download it.

Add signature to PDF

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