Sign a PDF on iPhone With Markup, Free

A lease, a contract, a school form, it lands as a PDF attachment and needs your signature back today. Before you go looking for a signing app, know that iPhone already does this natively through Markup, the same tool that lets you scribble on a screenshot. It works on any PDF, in Files, Mail, or Photos, and it’s genuinely built for this.

Signing a PDF you already have

1. Open the PDF, in Files, as a Mail attachment, or in another app that supports Markup.
2. Tap the Markup icon (a pen tip inside a circle), usually in the toolbar at the top or bottom of the screen.
3. Tap the + button in the Markup toolbar, then tap Add Signature.
4. If you have a saved signature already, tap it to select it. If not, sign your name with your finger (or Apple Pencil, if you have one) on the line that appears, then tap Done.
5. Your signature appears on the document as a movable object. Drag it into position, and drag any of the blue dots on its bounding box to resize it.
6. Tap Done to exit Markup, then share or save the signed PDF from the share sheet.

iPhone remembers the signature you created, so the next time you need to sign something, it’s already there to pick from, you don’t have to draw it fresh every time.

Creating, labeling, and managing signatures

You’re not limited to one signature. Inside the Add Signature screen, tap Add or Remove Signature to create a second one, useful if you want a full signature plus a separate set of initials for multi-page documents.

You can label each one (given name, nickname, initials) so you can tell them apart later. To redraw a signature you’re not happy with, tap Clear and sign again before saving it.

To delete an old signature, go back into Add Signature, tap Add or Remove Signature, and tap the remove icon next to the one you want gone.

Filling out the rest of the form first

If the PDF has actual form fields, not just a signature line, iOS can often detect them and let you fill them in before you get to the signature. Tap into any blank field and type using the keyboard.

If your Contacts app has your own info saved under My Card, iPhone can offer to auto-fill matching fields (name, address, and similar) in one tap instead of typing each one, worth checking before you fill things manually field by field.

Where this comes up in Mail specifically

If the PDF arrived as an email attachment, you don’t need to save it to Files first. Open the email, tap the attachment to preview it, and the Markup tool is available right from that preview. Sign it there and you can reply with the signed version attached without ever leaving Mail.

Why you don’t need a dedicated signing app

Third-party e-signature apps add value when you need audit trails, multiple signers, or legally-binding e-signature certificates for business use, that’s a real category and Markup doesn’t replace it.

But for the common case, a form or a one-off document that just needs your signature on it, Markup does the whole job with nothing to install, no account, no watermark stamped across the page, and no file uploaded anywhere. The signing happens entirely on your device.

Once it’s signed: merging or shrinking it

If you need to combine your signed page with other documents (a cover letter plus the signed form, for instance) into a single PDF before sending, that’s covered separately in merging PDF files on iPhone. And if the signed file is too large for an email attachment limit, compressing a PDF on iPhone walks through shrinking it without redoing the signature.

Frequently asked questions

Is a Markup signature on a PDF legally binding?

For most everyday documents, a handwritten-style signature added this way is treated the same as a physical signature. For contracts with strict e-signature requirements (real estate, certain legal filings), check what the other party or your jurisdiction specifically requires, some situations call for a certified e-signature service rather than a drawn signature image.

Can I sign a PDF without opening it in Files first?

Yes, if it arrived as a Mail attachment, you can tap to preview it right inside Mail and use Markup from there without saving a copy to Files at all.

Does the signature save with the PDF permanently?

Yes, once you tap Done in Markup and save or share the file, the signature is flattened into that copy of the PDF. If you need to sign a fresh, unsigned copy again later, start from the original file.

Can I use my finger, or do I need an Apple Pencil?

Your finger works fine for a basic signature. An Apple Pencil, on a compatible iPad or if you’re doing this on an iPad instead of iPhone, gives you finer control if your signature is more detailed.

What if the PDF is password protected?

You’ll need to enter the password to open it before Markup becomes available. Once it’s unlocked and displayed, signing works the same way described above.