Tutorials · September 28, 2026 · 5 min read
How to sign a PDF on a Mac: two free ways
Preview can sign a PDF in under a minute. Here is exactly how, and the situations where it starts to get in the way.
Every Mac comes with a PDF signer: Preview, the app that opens PDFs by default. For most one-off documents it is all you need. Here is how to use it well, and where it stops being the right tool.
Signing a PDF in Preview
Open the PDF in Preview. If it opens in a different app, Control-click the file and choose Open With, then Preview.
Before you change anything, consider making a copy with File, then Duplicate. Preview saves edits into the file itself, so if you might need the unsigned original, keep one now.
Click the Markup button, a pen tip in a circle, to show the Markup toolbar. Then click the Sign button, the one with a signature on it.
The first time, choose Create Signature. You can sign on the trackpad with a finger, pressing any key when you are done; hold a signature written on white paper up to the camera; or, on recent versions of macOS, sign on a nearby iPhone or iPad and watch it appear on the Mac.
Click your signature to drop it on the page, drag it onto the line, and resize it by its corners. Add the date and your printed name with the Text tool. Close the window, or press Command-S, and the signed PDF is saved.
Getting a good-looking trackpad signature
Sign larger than feels natural and slower than you normally would. The signature is scaled down onto the page, which smooths out the wobble. If it still looks shaky, the camera option is usually better: sign on white paper with a dark pen and hold it steady in good light.
Where Preview starts to get in the way
Dates and names are loose text boxes. You pick a size, then line each one up by eye, and for a long agreement with a date beside every signature that becomes the slow part.
It is Mac-only. When the colleague who has to countersign uses Windows, Preview cannot help them, and the built-in options on Windows are considerably weaker.
And it keeps no record. The signed file does not say when it was signed or whether it has been changed since, which rarely matters for a lunch order and sometimes matters a lot for a contract.
Signing in the browser instead
Open esign.website in Safari, Chrome or any other browser. Drag the PDF onto the page. It is opened and rendered on your Mac; the file is not uploaded.
In the panel beside the document, draw your signature or type it in a script font, then click Use this signature — or upload an image of your real one, which goes onto the page as soon as you choose it. It appears on the page: drag it into place, and use the arrow keys to nudge it a pixel at a time when it has to sit exactly on a line.
Date fields come in a choice of formats, alongside text, initials and checkboxes, and every page keeps its own fields; the Signature button adds your signature to whichever page you are on. Click Download PDF and choose Standard PDF, and the signed copy is saved straight to your Mac with a watermark. Clean PDF gives a clean copy for $1.
If the document needs a record, the $4 certified download adds a final page listing the file name, page count, time of signing and a SHA-256 fingerprint of the original document. Sign in before you download and it also carries a link anyone can use to verify it later.
Which one should you use?
For a single signature on a simple document, use Preview. It is free, it is already installed, and it takes under a minute once your signature is saved.
Use the browser for longer agreements with dates and initials throughout, when the same steps have to work for someone on Windows, or when you want a certificate page that shows what was signed and when.