How to Sign a PDF on a Mac

macOS comes with everything you need to sign a PDF without installing a single extra application. The Preview app, which ships with every Mac, includes a Markup toolbar that lets you draw, type, or even capture a signature using your trackpad or iPhone camera. For situations where Preview falls short, such as documents requiring a shared signing link or multi-party workflows, a browser-based tool is the cleaner option. This guide covers all the practical methods so you can choose the right one for your document.

Method 1: Sign Using Preview (Built-In)

Preview is macOS's default PDF and image viewer. It handles basic PDF signing well and requires no internet connection once the PDF is on your Mac. Open your PDF in Preview by double-clicking the file, or right-clicking and choosing Open With > Preview if another app is set as the default.

Once the PDF is open, click the Markup toolbar icon — it looks like a pencil inside a circle and sits at the top right of the toolbar row. If you do not see it, go to View > Show Markup Toolbar. The Markup tools will appear across the top of the window.

To add your signature, click the Signature button in the Markup toolbar. It looks like a script letter S or a hand-drawn squiggle. If this is your first time, Preview will prompt you to create a signature. You have three options: draw it on the trackpad using your finger, type your name and pick a handwriting font, or hold a written signature on paper in front of your Mac's FaceTime camera and Preview will capture it. The camera method produces the most natural-looking result.

Once your signature is saved, click the Signature button again and select it from the list. It will appear on the page as a moveable, resizable element. Drag it to the signature line and resize it by pulling the corner handles. When it looks right, click anywhere else on the document to deselect, then save the PDF with Command+S. The signature is now embedded in the file.

Method 2: Use Continuity — Sign from Your iPhone

If your Mac and iPhone are on the same Wi-Fi network and signed into the same Apple ID, you can use Continuity Camera to draw your signature on your iPhone's screen and have it appear directly in Preview on your Mac. This works well because your finger on a phone screen produces a much smoother, more controlled result than a trackpad.

With the Markup toolbar open in Preview, click the Signature button and choose Create Signature > iPhone or iPad. Your nearby iPhone will vibrate and show a drawing canvas. Sign your name with your finger in the white area, tap Done, and the signature appears in Preview instantly. From there, place and resize it as described above. This signed document then saves as a standard PDF — no special format required.

Method 3: Quick Look Markup

If you receive a PDF as an email attachment in Apple Mail and only need a quick signature without opening Preview fully, the Quick Look approach saves a step. In Mail, hover over the PDF attachment and click the dropdown arrow that appears on the attachment icon. Choose Markup. This opens Quick Look with the full Markup toolbar already active. Add your signature, click Done, and Mail will attach the annotated version directly to your reply. You never need to leave the email client.

When Preview Is Not Enough

Preview's signature tool works well for documents where only you need to sign and you are happy keeping the file local. It is less suited for a few common scenarios. If you need someone else to sign — a contractor, a client, a landlord — Preview cannot generate a shareable signing link. The recipient would need to have the file, open it in their own Preview, add their signature, and send it back, which creates versioning confusion.

Preview also does not produce an audit trail. There is no log of when the file was signed, from what device, or whether the document was altered after signing. For informal agreements this is usually fine. For contracts where you might ever need to prove who signed what and when, you need a tool that generates timestamped signing records.

Method 4: Sign Online Using a Browser Tool

For documents that need to go to another party or where you want a proper signing record, a browser-based signing tool is the better choice on a Mac. Sign Any PDF Free works directly in Safari or Chrome with no extension or plugin required. Go to signanypdffree.com, upload your PDF, place the signature field where it belongs, and generate a signing link.

You can send that link to anyone — they open it in any browser on any device, draw or type their signature, and the signed copy is ready to download. The whole exchange happens without either party needing to install anything. This approach is especially useful when the other person is on Windows, a phone, or any platform other than macOS, because they do not need Preview at all.

Exporting and Sharing the Signed PDF

After signing in Preview, the saved file is a standard PDF. You can share it by email, AirDrop, iMessage, or upload it to iCloud Drive, Google Drive, or any other cloud storage. The signature is rasterized into the document — it cannot be moved or edited without specialized software, which is the behavior you want from a security standpoint.

If the original document came from an editable form (a PDF with form fields), check after saving that the fields are flattened. Preview sometimes leaves interactive fields live, which means a recipient could theoretically change other fields even after you have signed. To flatten, go to File > Export as PDF, which bakes all annotations and form data into a static layer. This is a good habit for any signed document you plan to distribute.

Summary

For personal documents or quick turnarounds, Preview's built-in Signature tool combined with iPhone Continuity is one of the fastest free signing workflows available on any platform. For shared documents, multi-party signing, or situations where an audit trail matters, Sign Any PDF Free provides the missing pieces without requiring you to pay for a subscription or install additional software on your Mac.