You can sign a PDF without printing it using free tools you probably already have: the Fill & Sign tool in Adobe Acrobat Reader, the Sign button in Preview on a Mac, or Markup on an iPhone. Each one lets you type, draw, or capture your signature and drop it onto the page. If other people also need to sign, that’s a different job, and an e-signature service handles it better.

Here’s how each option works, based on the vendors’ own help pages, plus some honest notes on when each one makes sense.

What’s the easiest free way to sign a PDF?

The free Adobe Acrobat Reader is the easiest option that works on almost any computer. Adobe states that Acrobat Reader “is free to download and use without a subscription,” and its Fill & Sign tool lets you type or draw your signature, or use an image of it.

If you’re on a Mac, you don’t even need to install anything, because Preview can do it. On an iPhone, the built-in Markup tools cover it too. Which one to use mostly comes down to the device you’re holding when the PDF lands in your inbox.

How do I sign a PDF in Adobe Acrobat Reader?

Open the PDF in Acrobat, select E-Sign from the global bar (or go to All tools > Fill & Sign), then choose Add your signature or initials from the Quick action toolbar. Here’s the full sequence from Adobe’s help page:

  1. Open the PDF in Acrobat Reader.
  2. Select E-Sign from the global bar. If you don’t see it, select All tools > Fill & Sign.
  3. In the Quick action toolbar, select Add your signature or initials, then Add signature.
  4. Type or draw your signature, then select Done. You can also use an image of your signature: the image icon adds an existing picture, and the camera icon lets you take a new one.
  5. Place the signature. Hover over it until you see a plus icon, then click and drag it where it belongs. To resize, drag the blue circle at the corner.
  6. Save the file.

One thing to watch: Adobe says that once you add a signature or initials and save, “you cannot edit it again.” If there’s any chance you’ll need to fix something (a wrong date next to your signature, say), keep an unsigned copy first.

Adobe has been rolling out a redesigned Acrobat interface, so if your screen doesn’t match these labels exactly, look for Fill & Sign under All tools.

How do I sign a PDF on a Mac with Preview?

Open the PDF in Preview, click the Show Markup Toolbar button if the toolbar isn’t visible, then click the Sign button. From there, Apple gives you three ways to create a signature:

  • Trackpad: click Trackpad, sign with your finger on the trackpad, press any key, then click Done.
  • Camera: click Camera, sign your name on white paper, hold it up facing the camera until it appears in the window, then click Done.
  • iPhone or iPad: click Select Device, choose your device, sign on its screen with your finger or an Apple Pencil, then tap Done. Apple notes the devices need to meet Continuity system requirements for this to work.

Once the signature exists, click it to add it to the document, drag it where you want it, and use the handles to adjust the size.

The camera option is the one people overlook, and it’s the one I’d use. Signing on a trackpad with a fingertip tends to produce something that looks like a seismograph reading. A pen on paper held up to the webcam gives you your real signature.

For a lease renewal or a school form, Preview does everything you need.

How do I sign a PDF on an iPhone?

Open the PDF on your iPhone, tap the Add button, tap Add Signature, sign with your finger, tap Done, then drag the signature where it should go. Apple’s steps (from its iPhone User Guide, current version iOS 27):

  1. Open the form or document. If prompted, open it in the Files app, then tap Save.
  2. To fill in blank fields, tap the AutoFill button, tap a field, and type. If you’ve filled out your My Card in Contacts, AutoFill can complete supported fields for you.
  3. To sign, tap the Add button, tap Add Signature, sign your name with your finger, then tap Done.
  4. Drag the signature into place.
  5. When you’re finished, you can export, print, or share the completed document.

Apple also has a tip that genuinely helps: rotate your iPhone to get more room to sign.

In supported apps such as Notes and Photos, you can do the same thing from the Markup toolbar: tap the Markup button, tap the Add button, then tap Add Signature. iPhone saves your signature for next time, and you can create more than one (initials, for instance) and label them.

It’s the fastest option when a landlord or a school sends something that needs a signature today and you’re nowhere near a laptop.

What if more than one person needs to sign?

When two or more people need to sign, a tool that just places your own signature starts to feel clunky. You sign, email the PDF, the other person signs their copy, emails it back, and now there are three versions floating around and nobody’s sure which is final.

Picture this: you run a fencing company and need a homeowner and their spouse to both approve a $3,900 quote. With Preview, you’d be emailing attachments back and forth and hoping everyone signs the same file. An e-signature service does the routing for you. You upload the PDF once, place a signature field for each person, and send it. The service tracks who has signed, and everyone ends up with the same completed copy. We walk through signing order, reminders, and CCs in how to get a document signed by multiple people.

If your team is on Google Workspace, check whether you have Google’s eSignature feature. Google says it’s available on Workspace Individual accounts and several business and enterprise plans (when an admin turns it on), plus Education Plus. For a PDF stored in Google Drive, open the file and click Menu > eSignature; in a Google Doc it’s Tools > eSignature. Then drag in the fields you need (signature, initials, name, date signed and so on) and assign each one to a signer. Only after that does Request signature come into play: click it, give the PDF a title, enter each signer’s email, and click Request signature again to send. It’s a reasonable choice if you’re already paying for one of those plans.

Is a signature pasted onto a PDF actually valid?

Whether a drawn or typed signature on a PDF is enough depends on the document and on what the other side will accept. The legal side is its own topic, and we cover it in are electronic signatures legally binding.

There’s a practical difference to understand too. The signatures you add with Fill & Sign, Preview, or iPhone Markup are marks on the page. They don’t lock the rest of the document, so they don’t show whether someone changed the text after you signed. Certificate-based digital signatures and e-signature services that seal the final file are built to address that. If that matters for your document, read how to check if a signed PDF was altered.

For most one-person signing jobs, any of the free tools above will do. We also made a free Sign a PDF tool that works in any browser and never uploads your file. When you’re sending documents out to clients and need everyone to sign the same file with a record of who signed when, that’s the gap SignWren is being built for. Join the waitlist if you want early access.