All the ways to digitally sign a PDF

You don't need a pen to put down your signature on a PDF file.
A person signing a PDF document on their phone
You can sign PDF documents on your phone and on the go. DocuSign / Unsplash

Paper copies and filing cabinets have become less common since cloud computing became more ubiquitous. But you may still need to sign a PDF document, which may be a problem if you don’t have a printer and scanner handy.

The solution is to do everything digitally, scribbling your signature with your finger, a stylus, or a mouse cursor, and pasting it on the PDF. There are multiple different ways to go about it, so you can choose the one that suits you best.

 How to sign a PDF document on Windows

Person signing a document on Microsoft Edge
On Microsoft Edge, you can choose the width and color of the lines you’ll use to draw your signature. David Nield for Popular Science

If you’re looking for a built-in PDF signing tool in Windows, your best option is the Microsoft Edge browser that comes with the operating system. To open a file, drag it into a browser tab from File Explorer or press Ctrl+O and select the document.

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Up at the top of the screen, you’ll see a new toolbar: Click the small arrow next to Draw to choose the color and line thickness of your signature. With that done, leave your mark on the document using your mouse or trackpad. You may also use your finger if your Windows device has a touchscreen.

If you don’t like your digitized autograph and need to start again, click the icon that looks like an eraser. Once you’re happy with the result, head over to the save icons you’ll see up in the top-right corner of your screen—they look like floppy disks. Click the one on the left to save over the original PDF or the one on the right (with the pen icon) to save the signed document as a new file.

How to sign a PDF document on macOS

A person signing a PDF document on Preview on MacOS.
Preview, on macOS, will automatically save your signature and even share it with other Apple products signed into the same account. David Nield for Popular Science

Over on Apple’s desktop operating system, your native PDF-signing tool is the easy-to-use  Preview. By default, all PDFs should open in the tool by double-clicking on them, but if that’s not the case, you can always summon the app via Spotlight search: type “preview” on the search bar that appears when you hit command + spacebar. Select the program and then open the document from there by going to File and clicking Open

Once Preview is displaying the relevant file, you should see an icon on the toolbar at the top that looks like a signature. If you don’t see the option, go to View and click on Show Markup Toolbar—it’s towards the bottom of the menu. Click the signature button and choose Create Signature. There are several ways to go about it: You can scrawl your autograph on your trackpad, you can hold a piece of paper with your signature on it up to your Mac’s webcam, or you can sign using your finger or an Apple Pencil on an iPhone or iPad linked to the same Apple ID as your computer.

When you’re done with the result, click Done and your scribble will drop into the document, where you’ll be able to reposition and resize it as needed. Your signature will automatically save for future use, so next time you open a document on Preview, you can click on the signature icon and your autograph will be there ready to be inserted wherever you need it.   

To save over the current PDF, choose File and then Save; or if you’d rather create a new file, choose File and Export instead.

How to sign a PDF file on Android

A person signing a PDF document on an Android device
For Android owners, the easiest way to sign a document is to open it on the Google Drive app. David Nield for Popular Science

If you want to sign a PDF on Android you don’t need the hassle of downloading and signing up for another app—Google Drive, which should already be on your device, has you covered. Open up a PDF, then tap the edit button (bottom right), which looks like a pen with a scribble next to it.

Tap the pen tool (bottom left) and choose a color and line thickness for your signature. With that done, you can sign right on the document. Use the eraser or the undo (backward arrow) buttons on the toolbar to go back and start again, if you need to. You can then tap Save to overwrite the PDF, or tap the three dots (top right) and Save copy to create a separate file.

And if you don’t want to use Google Drive, Android has plenty of third-party options to pick from, as well. Adobe Fill & Sign can scan a written signature you’ve got on a piece of paper for example, while JetSign can work with other types of files (like Word documents) as well as PDFs.

How to sign a PDF on iOS or iPadOS

A person signing a PDF document on an iPhone
Apple products will share the signatures that you create among them so that you can sign PDF files no matter the Apple device you’re on. David Nield for Popular Science

The digital signing features on iOS and iPadOS closely match those on macOS, and you’ll find the relevant tools in the Files app. Open a PDF in Files, then tap the icon in the bottom right corner that looks like a pen filling out a form. This brings up a list of your existing signatures, including ones you might have created on your Mac.

You can also tap Add or Remove Signature and the + (plus) icon to create a new scribble using your finger or an Apple Pencil. Once you’ve selected a signature, you can reposition it on the document by dragging it around with your finger, and resize it by moving the blue handles around the edges. Tap Done to overwrite the existing file. If you want a separate copy, tap the file name (top left) and then Duplicate.

As you would expect, plenty of third-party apps for iOS and iPadOS will take over PDF signing duties if you need them to. PDF Expert gives you access to a host of PDF editing tools, including the ability to add signatures, while SignNow is a good choice if multiple people need to sign the same file.

Other options to sign a PDF document

A person signing a document on Dropbox
If you want to explore more options to sign your documents, Adobe, DocuSign, and Dropbox, among others, offer alternatives. David Nield for Popular Science

If you want to test and compare several tools, there are yet more options you can try out. If your PDF documents are in Dropbox, you can open them up on the web, then click Add signatures and Self-sign to add your autograph. You can draw using your mouse or trackpad, create a signature based on a font of your choice, or upload an image of your signature from somewhere else.

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DocuSign also offers a comprehensive set of document-signing tools. Click your profile picture (top right), then Manage Profile and Signatures to assign your personal scribbles to your account, which you can then add to any of your documents. If multiple parties are signing the same document, DocuSign can keep track of who has signed what, and when.

If you want something simple that runs in your browser, you can rely upon ILovePDF for any kind of PDF editing or processing task. Just click Sign PDF and follow the instructions on the screen. You can scribble out a signature with your mouse or trackpad, upload an image of your signature, or generate one using your name and font of your choice.