How to Have Preview Sign Your PDFs in OS X

| How-To

I continue to marvel at the utility that the Preview app in OS X delivers. Even though Preview is categorized as a PDF and image viewer, a little-known feature is that it also allows you to edit those PDF files and images. We'll discuss the image-handling abilities in a new article soon, but for today, let's look at one aspect of PDF editing: inserting a signature.

An example of an official document that was signed within Preview.

You can place a signature stored within Preview anywhere on a PDF document. If you'd like, you can set the color, too.

Why would you want to do this? Perhaps the biggest reason is that signed legal documents in PDF format are becoming used – and accepted – more and more each day. Thankfully, the outdated facsimile machine is going by the way of the floppy drive, the acoustical modem and the mouse. In fact, any business that still requires faxed documents – well, I don't give them my business. The winds of time have disintegrated my fax machine, and going out to get things faxed is embarrassing.

Enter Mountain Lion and Preview with a new Signature feature. You can now have Preview scan and store your signature for use at any time.

Of course, you first need to create one or more signatures to keep on file within your copy of Preview. My copy maintains a full-name version of my signature, a shortened version, my initials, and my wife's signatures as well.

To manage the Signatures feature, go to Preview > Preferences and click on the Signatures tab.

You need to prepare your signature ahead of time by signing on a white sheet of paper. I like using a black or blue super-fine Sharpie, but a pencil works well, too.

Next, lets get your scribble into Preview. This one-time procedure couldn't be simpler, and you are prompted along the way:

1. Click on "Create Signature."

The Signatures pane of Preview Settings gives you instructions on creating a new signature.

The Signatures pane of Preview Settings gives you instructions on creating a new signature.

2. In the Signature Capture panel that appears, hold the paper up to your Mac's camera. While referring to the video window, position the paper to ensure your signature fills the box and sits on the blue baseline.

While you're at it, notice the checkbox for enabling a feature whereby Preview will save the scanned signature. This allows you to create a single-use signature – a feature that's particularly convenient for the super-paranoid or when using someone else's Mac.

The Signature Capture panel in Preview.

Holding up your signed piece of paper to the Mac's camera, the Signature Capture panel provides feedback to help you properly position your signature.

3. When the signature preview looks just right, click Accept or press Return.

That's it!

Now, let's have Preview sign a document for you.

First, click the Show Edit Toolbar button in Preview's toolbar. This opens up the Edit Toolbar where all the annotation tools are located. One of these is the Signature Tool. Click on the Signature Tool to pop-up a menu where one or more of your signatures will appear. Click the signature you wish to use.

Locate the spot on the PDF document where you want the signature to appear, and click there. In most situations, if you click right on a signature line, Preview will shrink the signature to fit on it.

Clicking on the Signatures button located in the Edit Tools bar reveals a list of your stored signatures that you can choose from to have inserted in your PDF document.

You can choose from the list of signatures that appears when clicking on the Signatures button located in the Edit Tools bar.

You can resize your signature by clicking on it and using the resize handles. You can also relocate the signature by dragging it anywhere on the document. With the signature selected, you can also change it's color via the Color popup menu in the Edit Bar. By the way, it's very helpful that the signature supports image transparency, allowing any text or objects behind the placed signature to show unimpeded.

In the Signature popup menu that appears when clicking on the Signature Tool button, notice the commands listed at the bottom; commands to Create new signatures and to Manage your signatures.

In the Manage Signatures panel, use the + and buttons at the bottom to create additional signatures or to delete selected signatures.

The Signatures pane of Preview Settings now allows you to manage any stored signatures.

The Signatures pane of Preview Settings now allows you to manage any stored signatures as well as to create new ones.

As you discover new features in Preview, doesn't it become more apparent how truly valuable this Apple pre-installed app can be in your workflow? Why not give Preview's new Signature feature a try? I'm sure you can find other uses for it, because… it's not just for signatures!

Popular TMO Stories



My wife has a Macbook Pro and I have a Mac Pro. Her system has a camera but mine doesn’t. Is there a way I can capture my signature on her machine and then transfer it over to my machine so that my Preview can access it?


Ladd, I think you will find the answer at


There are several things which would make this article clearer.

1) This works only for PDFs, not PNGs
2) The tool bar is located under VIEW/SHOW EDIT TOOLBAR, or type Shift-CMD-A, or click on the ICON with the pencil across a square (the Show Edit Toolbar - not obvious)

Finally, it doesn’t work.  I have tried 50 times to put my signature on a PDF and nothing happens.  Now what?


Well, it certinly works…

Bart B

Thanks so much for avoiding the phrase “digital signature” in this article. A few weeks ago I tried to do a search for OS X software for digitally signing documents, and the results were utterly poluted with people trying to write articles like this one (and not doing it as well), and wrongly calling this kind of copy and paste of an image a digital signature.

For anyone wondering what I am on about, an actual digital signature is a cryptographic way of validating a document, guaranteeing that:
1) the document comes from the person it claims to come from
2) that the document has not been altered in transit

It’s very useful that Preview is allowing this feature, but it horrifies me that anyone would accept this as any sort of proof at all that you have agreed to anything. Anyone could paste in a photo of my signature!

In a digital world, we need actual digital signatures, not meaningless pretty pictures!


@Bart B: Adobe Acrobat does digital signatures.


My signature appears rotated thru 90 degrees on many of the PDFs I’ve tried to sign.  My workaround is to rotate the paper when I scan a signature!


The continuing use of fax machines is not due so much to companies as it is too the law that governs document acceptance.

In many instances a lawyer cannot rely upon email or other electronic document as a proper way to accept specific “instructions” (the formal legal instructions telling your lawyer what to do). But he/she can accept that same thing delivered by fax. Why the difference? Long legal practice.

As one comment notes, the PDF scheme is eminently forgeable. What we do need is widespread use and acceptance of real digital signatures. After all, the enabling legislation was signed by President Bill Clinton! It’s that long ago!

Jane Kim

When I re-open the document back in pdf (after having signed it in Preview), all fields are blank but the signature is there all alone. Escalated level of Apple support blamed it all on PDF Pro and had no solution. I have MacBook Air 2011 OSX 10.8

Log in to comment (TMO, Twitter or Facebook) or Register for a TMO account