How to Sign a PDF on Mac with Preview (Step by Step)

Someone emails you a contract, a permission form, or an agreement as a PDF and asks you to “sign and return.” Printing, signing by hand, and scanning is slow — and completely unnecessary on a Mac. The built-in Preview app can capture your real signature with the trackpad or camera, save it, and stamp it onto any PDF in seconds. This guide shows you how to create your signature, place it neatly on the line, save the signed copy safely, and fix the usual problems people run into.

Quick Answer

Open the PDF in Preview, click the Markup toolbar button (the pen icon), then click the Sign icon. Create a signature by drawing it on your trackpad, holding your paper signature up to the camera, or writing on a connected iPhone. Then click the saved signature to drop it onto the page, drag it onto the signature line, resize it with the corner handles, and save or export the signed PDF.

Step 1: Open the PDF in Preview

1. Find the PDF in Finder and double-click it — most Macs open PDFs in Preview by default.
2. If it opens in another app, right-click the file, choose Open With, then Preview.
3. Click the Markup button in the toolbar — it looks like a pen tip inside a circle. The markup tools appear below the toolbar.

If you cannot see the Markup button, choose View from the menu bar, then Show Markup Toolbar, or press Command + Shift + A.

Step 2: Create Your Signature

Click the Sign icon (it looks like a small signature) and choose Create Signature. Preview offers up to three ways to make one:

Option A: Draw on the trackpad

1. Select the Trackpad tab and click to begin.
2. Sign your name on the trackpad with your fingertip, moving in one smooth motion.
3. Press any key when finished. Unhappy with it? Click Clear and try again.
4. Click Done to save it.

Trackpad signatures look best when you sign a little larger and slower than usual, and use the pad of your finger rather than the very tip.

Option B: Use the camera

1. Sign your name in dark ink on plain white paper.
2. Select the Camera tab in the signature window.
3. Hold the paper up to the Mac’s camera so your signature sits on the blue line shown on screen.
4. Preview extracts the signature and flips it correctly. Click Done.

Camera capture usually produces the most natural result because it is your genuine handwriting.

Option C: Sign on your iPhone

If your iPhone is signed in to the same Apple account, an iPhone tab may appear. Choose it, sign on the phone’s screen with your finger, tap Done there, and the signature arrives on your Mac ready to use.

Your signatures are stored in Preview and synced through iCloud, so a signature you create once is available on your other Apple devices too. Apple’s Preview forms and signatures guide on Apple Support shows the same workflow with illustrations.

Step 3: Place the Signature on the Document

1. Click the Sign icon and choose your saved signature. It appears on the page inside a selection box.
2. Drag it to the signature line. Use the arrow keys for tiny nudges once it is nearly in place.
3. Resize it by dragging a corner handle so it matches the size of printed text around it — oversized signatures look unprofessional.
4. Click outside the signature to set it. Need the date too? Use the Text tool (the T icon) to type the date beside it in a matching style.
5. If the form has fillable fields, click each field and type; Preview handles proper PDF forms as well as flat scans.

Made a positioning error? The signature stays selectable: click it once to select, drag it again, or press Delete and re-add it from the Sign menu.

Step 4: Save and Send the Signed PDF

This step matters more than people realise:

1. Choose File, then Save if you want to overwrite the original, or File, then Export to keep an untouched original and save the signed version as a new file with a clear name like Contract-Signed.pdf.
2. In the Export dialog, keep the format as PDF.
3. Important: ticking Embed this signature permanently is not an option here — Preview flattens your additions into the saved page automatically when you export, which is what you want for sending. Simply attach the new file to your reply email.

Keeping the unsigned original is a good habit for contracts, because it proves which version you received. If you are assembling a packet of documents, our guide on editing and annotating PDFs in Mac Preview covers highlighting, notes, and page rearrangement that often go together with signing.

Sign on a Form with Many Pages

Long agreements sometimes need initials on several pages. Your saved signature stays one click away in the Sign menu, so the routine is fast: scroll to each page, Sign, choose signature, drag into place. For initials, create a second “signature” that is just your initials using the same Create Signature steps, and name them distinctly in the list.

Common Mistakes and Helpful Tips

• Signing the received file and overwriting it. Always export a signed copy so the original stays unchanged in your records.
• A signature that looks like a child’s drawing. Trackpad signing takes two or three attempts. Use the camera method for a truly natural signature.
• Placing the signature but forgetting other fields. Many forms also need printed name, date, and address. Fill every field before exporting.
• Giant signature syndrome. Scale the signature so its height roughly matches two lines of the document’s printed text.
• Assuming Preview signatures are legal certificates. A drawn signature is fine for most everyday forms, but documents needing a certified digital signature (some legal, banking, or government filings) require dedicated signing services — the sender will tell you if so.
• Signature missing from the Sign menu. Click Create Signature again; if the menu is greyed out, make sure you opened a PDF (not an image) and that the Markup toolbar is visible.

Conclusion

Preview turns signing a PDF into a two-minute job: create your signature once with the trackpad, camera, or iPhone, then stamp it onto any form from the Sign menu and export a signed copy. No printer, no scanner, and no extra software. Keep the original file untouched, size the signature sensibly, and your returned documents will look clean and professional every time.

Frequently Asked Questions

Is a signature made in Preview legally acceptable?

For most everyday documents — school forms, simple contracts, permission slips — a hand-drawn signature image is widely accepted. Documents that legally require a certified digital signature will say so, and those need a specialist signing service instead.

Where is my signature stored, and can I delete it?

Signatures live in Preview’s Sign menu and sync via iCloud to your other Apple devices. To delete one, open the Sign menu, hover over the signature, and click the small X that appears beside it.

Can I sign a PDF that someone sent as a photo or scan?

Yes. If the “PDF” is really an image of a form, open it in Preview and use the same Sign tools — the signature becomes part of the exported file. For a true PDF, the workflow above applies directly.

Why is the Sign button greyed out?

Usually because the Markup toolbar is hidden or the file is not editable. Show the Markup toolbar from the View menu, and if the PDF is locked, ask the sender for an unlocked copy.

Can I add my signature to a Word document instead?

Export or save the Word file as a PDF first, then sign it in Preview. Signing the final PDF also prevents accidental edits to the document text afterwards.