How to add a signature to a PDF on Mac

To add a signature to a PDF on a Mac, open the file in Safari or Chrome at pdfviewer.work, click Signature, draw it on the trackpad and click where it belongs, then Download. Preview, which is already on every Mac, can do it too with its Markup Sign tool. Both keep the document on your Mac; here is how each works and when to pick which.

Sign a PDF in Safari or Chrome on a Mac

1. Open the PDF. Drag it from Finder onto this page, or click Open a PDF. The sign PDF tool page is the same tool.
2. Click Signature. Draw your signature in the pad with one finger on the trackpad, or with the mouse. Slow strokes come out cleaner than fast ones.
3. Click on the signature line to place it. If it is off, pick Eraser, click the signature, and place it again.
4. Add the date and your printed name with Text if the form asks for them.
5. Click Download. Safari saves the signed copy to your Downloads folder; the original stays as it was.

This route works the same on a MacBook, an iMac, a Windows laptop at the office or an iPad, which is useful if you sign documents on more than one machine. The PDF viewer for Mac page covers the rest of the toolbar.

Sign a PDF with Preview's Markup tool

1. Open the PDF in Preview (double-click it in Finder, unless another app has taken over PDFs).
2. Click the Markup toolbar button (the pen tip in a circle), then the Sign button.
3. Create a signature: Trackpad (draw with a finger, press any key when done), Camera (sign on white paper and hold it up), or iPhone (sign on the phone's screen).
4. Click the saved signature to drop it on the page, then drag it to the line and resize with the corner handles.
5. Press Cmd+S. Preview writes into the same file, so duplicate it first if you want to keep an unsigned copy.

Preview keeps the signature for reuse on the Mac, so the second document is one click. See PDF Viewer vs Preview for a side-by-side of the two.

Preview or the browser viewer: which to use on a Mac

Neither one produces a certificate-based digital signature; both place an image of your handwriting. If the recipient demands a digital ID, use Adobe Acrobat's Certificates tool or the signing service they name.

Sending the signed PDF from your Mac

After Download, the signed copy lands in your Downloads folder. Press Space on it in Finder for a Quick Look preview and confirm the signature sits on the line and the date is readable; it takes five seconds and catches a misplaced signature before the recipient does. Then drag it into Mail or Messages, or use the share button in Finder.

If the other party will print the document, there is nothing extra to do: the signature is drawn into the page and prints with it. If they will sign after you, they can open the same file in Preview, the viewer or Acrobat and add theirs; your signature stays put. Keep the unsigned original too, in case the terms change and a clean copy is needed.

For documents you sign weekly, the choice is a matter of habit: Preview if you like a stored signature and Cmd+S, the browser viewer if the same document also needs a page rotated, a restriction removed or a note typed in Arabic or Cyrillic.

Troubleshooting on a Mac

• No Markup toolbar in Preview. Choose View, Show Markup Toolbar, or press Shift+Cmd+A.
• The signature field in the form does nothing. It is a form field. In the viewer, draw the signature over it; in Preview, drop the saved signature on it.
• Preview says the file is locked. The PDF carries permission restrictions. Open it at pdfviewer.work, click Remove Restrictions, download the copy, then sign that.
• The file asks for a password. Enter it in Preview and save a copy with File, Print, PDF, Save as PDF. The browser viewer cannot open encrypted PDFs; the password guide explains why.
• The signature looks too big or small in the viewer. Remove it with the Eraser, redraw it to fill the pad, and place it again.

Frequently asked questions