To sign a PDF on a Mac, open it in Preview, click the Show Markup Toolbar button, click Sign, and create a signature with your trackpad, your Mac’s camera or a nearby iPhone or iPad. Then click the signature to drop it on the page, drag it into place and resize it with the handles. No download, no printer.
That covers most people. Below are the exact steps from Apple’s current Preview User Guide (the one written for macOS 27), a faster route straight from Finder, how the free Adobe Acrobat Reader handles it, and what to do when someone else has to sign as well.
What’s the easiest way to sign a PDF on a Mac?
The easiest way to sign a PDF on a Mac is Preview, the PDF and image app built into macOS. It’s built in, it remembers your signature after the first time, and it handles the most common job (sign a form, send it back) in under a minute.
You only need something else if you want a signature that locks the document, or you need other people to sign the same file. We’ll get to both.
How do I sign a PDF in Preview?
Open the PDF in Preview, click the Show Markup Toolbar button if the toolbar isn’t showing, then click the Sign button. Apple’s steps from there:
- If you already have a saved signature, skip ahead to step 3.
- Create a signature using one of the three methods below (trackpad, camera, or iPhone or iPad), then click Done.
- Click the signature you want in the list. It lands on the page.
- Drag it to where it belongs.
- Use the handles around it to make it bigger or smaller.
Then save the file and send it.
Which signature method looks best?
Of the three ways Preview lets you create a signature, the camera usually gives the most natural result, because it captures your real pen signature from paper. Here’s how each one works, per Apple:
- Trackpad. Click Trackpad, follow the prompt, sign with your finger, press any key, then click Done. On a Force Touch trackpad, pressing harder gives a heavier, darker line. Click Clear to start over.
- Camera. Click Camera, sign your name on white paper, and hold it up facing the camera so the signature sits level with the blue line. When it appears in the window, click Done.
- iPhone or iPad. Click Select Device (and pick a device if you have more than one nearby), then sign on its screen with your finger or an Apple Pencil and tap Done. Apple says your devices need to meet the Continuity system requirements for this one.
A fingertip on a trackpad rarely produces anything that looks like your actual signature. If the result bothers you, sign on paper with a dark pen and use the camera. If you have an iPad and an Apple Pencil, that’s even better.
Can you sign a PDF from Finder without opening Preview?
Yes, you can sign a PDF straight from Finder using Markup in Quick Look. Select the file, open it in Quick Look, click the Markup button, then click the Sign tool and pick a saved signature or click Create Signature. Apple’s Mark up files guide says the same Markup tools are also available as a Quick Action, if you’d rather choose Markup from there.
The signature options are identical to Preview’s: trackpad, built-in camera, or iPhone or iPad. Click Done when you’re finished.
One warning from Apple’s own page: in the Quick Look or Quick Actions window, you can click Revert to throw away your changes while the window is open, but once you close it, the changes can’t be undone. If there’s any chance you’ll need the unsigned version, duplicate the file first.
Where does your Mac store your signature?
Your Mac saves the signature you create in Preview and offers it again in apps that use Markup, and Apple says saved signatures also appear on your other Macs that have iCloud Drive turned on.
To delete one, open any file, show the Markup toolbar, click Sign, point at the signature and click the X next to it. Apple notes this removes it from every app that uses Markup on your Mac, and from your other Macs if iCloud Drive is on. That’s handy if you made a wobbly trackpad signature and want it gone everywhere.
How do you fill in the rest of the form before signing?
To fill out a PDF form in Preview, click a field and type. If the PDF won’t let you type in its fields, click the Show Form Filling Toolbar button, then the Text Box Tool button, and add a text box where you need it.
Preview can also fill your name and address for you. Click the AutoFill Form button above the PDF, or click a field, and choose your name from the menu; the details come from your card in Contacts. Apple says not every PDF supports AutoFill, so check what it entered. Our guide on how to fill out a PDF form covers trickier forms.
How do you sign a PDF someone emailed you?
To sign a PDF attachment in Mail, double-click it so it opens in Preview, sign it, then choose File > Save and pick Reply to Sender or New Mail Message. Mail opens a new email with the signed PDF already attached.
If the attachment opens in another app instead, close it, Control-click the attachment, choose Open With, and pick Preview.
How do you sign a PDF on a Mac with Adobe Acrobat Reader?
Open the PDF in Acrobat Reader, click the Sign icon in the toolbar (or choose Tools > Fill & Sign), choose to add a signature or initials, and type, draw or pick an image of your signature. Click Apply, then click where it should go and save the file. Adobe says the signature then becomes part of the PDF.
Adobe states Acrobat Reader is “free to download and use, with no subscription required,” and lists macOS 10.15 (Catalina) and later as supported. If you sign while logged in with Save Signature selected, the signature is stored in Adobe’s Document Cloud so you can reuse it.
Is it worth installing on a Mac? For most people, no, since Preview does the same job. It makes sense if your office already uses Acrobat, or if you’re signing a document that was sent through Adobe’s own signing service.
Is a signature from Preview the same as a digital signature?
No. Preview places an image of your signature on the page, while a digital signature uses a certificate to prove who signed and that the file hasn’t changed since. A Preview signature is perfectly normal for a permission slip or a signed quote, but it doesn’t lock the rest of the PDF.
If you need the certificate kind, read how to digitally sign a PDF. If you’ve received a signed PDF and want to know whether anyone edited it afterwards, how to check if a signed PDF was altered explains what to look for.
What if someone else needs to sign the PDF too?
When another person has to sign, Preview stops being the right tool, because it only adds your own signature to your own copy. You’d sign, email it, wait for them to sign their copy, and hope nobody changed a word in between.
Take a hypothetical: you run a two-person photography business and need both a bride and groom to sign a $2,800 wedding contract. With Preview, that’s three emails and possibly two different versions of the contract. An e-signature service sends one link to each person, collects both signatures on the same document, and records who signed when. How to get a document signed by multiple people explains signing order and reminders, and how to sign a PDF online compares the free tools if you’re on a computer that isn’t a Mac. If the original is a Word file, how to electronically sign a Word document covers that side. SignWren handles that part, with one sealed PDF and an audit trail for everyone at the end. You can start free.