How to Sign a PDF Document in Preview on Mac

Mac users often forget how capable Preview really is. Beyond viewing images and PDFs, it also includes a built-in signing feature. Meaning you don’t need to buy or install additional apps just to sign a document.

Let’s walk through how to sign PDFs on macOS with Preview, plus what to do when you need something more advanced.

How to Sign a PDF in Preview: Step-by-Step

Step 1: Open the PDF in Preview

Preview comes installed on every Mac. If it’s on your Dock, just drag the PDF onto it. If not, click the Spotlight Search icon (the magnifying glass in the top-right corner of your screen), type “Preview”, and press Enter. Select your PDF and it will open in Preview.

Step 2: Show the Markup Toolbar

Look at the top-right corner of the Preview window, just beside the search box. Click the Show Markup Toolbar button — it looks like a small pen tip inside a circle. A new toolbar will appear beneath the main menu with options for text, shapes, and the signature tool.

Step 3: Open the Signature Menu

On the Markup toolbar, click the Sign button — represented by a fountain pen icon.

• If you’ve signed a PDF before, your saved signatures will appear in a drop-down list.
• If not, you’ll see the option to Create Signature.

Step 4: Create a Signature (If Needed)

If you don’t already have a signature saved, you can create one using one of these methods:

• Trackpad: Select Trackpad, click Click Here to Begin, then sign with your finger or a stylus. Press any key when you’re done.
• Camera: Select Camera and hold up a white piece of paper with your signature in dark ink. Align it in front of your Mac’s camera, and Preview will capture a digital version.
• iPhone or iPad (macOS Catalina+): If your Apple devices are connected, choose iPhone or iPad and sign directly on the touchscreen. Once saved, your signature will always be available in the Sign menu.

Step 5: Place Your Signature

Click your signature in the drop-down menu. It will appear on the PDF page.

• Drag it to the correct location (for example, the bottom of a form).
• Use the corner handles to resize it so it looks natural.

Step 6: Save Your Signed PDF

Go to File > Save, or press Command + S. Your document now contains your signature and is ready to share.

Can You Digitally Sign a PDF in Preview?

Preview only supports electronic signatures — essentially an image of your handwritten signature. This works for most everyday documents, but it doesn’t create a cryptographic digital signature that proves authenticity.

• Electronic signature (Preview): Simple image, good for personal or informal documents.
• Digital signature (Smallpdf Sign PDF): Certificate-based, secure, legally binding in many jurisdictions.

If you’re signing contracts, compliance forms, or anything requiring verification, use Sign PDF for a proper digital signature. It’s very simple and easy to use, as you can see:

Troubleshooting: What If You Can’t Sign in Preview?

Sometimes the Sign option is greyed out or won’t let you insert your signature. Common reasons:

• The PDF is secured. Locked PDFs may block signing until restrictions are removed.
• The file is just a scan. You can still place your signature, but the text won’t be editable.
• You haven’t set up a signature yet. Click Create Signature in the Sign menu to add one.

If you’re still stuck, upload your file to Edit PDF to place your saved signature image, or use Smallpdf Sign PDF for a digital signing workflow.

When to Use Preview vs. Smallpdf

• Preview is best when you need a quick, offline solution for personal files.
• Smallpdf is better when you need digital security, cloud storage, or to request signatures from others.

Both can get the job done — it depends on the level of formality and security your document requires.

FAQs

1. Can I sign a PDF in Mac Preview?

Yes. Open the file in Preview, click the Show Markup Toolbar, then the Sign icon, and either insert a saved signature or create a new one.

2. How to enable signature in PDF in Mac?

In Preview, open the Markup toolbar and click the Sign icon. If no signature is saved, use the trackpad, camera, or iPhone/iPad to create one.

3. How to sign a PDF on a Mac without Adobe?

Preview handles this directly. If you need a secure digital signature, use Smallpdf’s Sign PDF instead of installing Adobe.

4. How do I electronically sign a PDF?

In Preview, insert your signature image. For a verified digital signature, use an online signing platform like Smallpdf Sign PDF.