How to Sign a PDF on iPhone or iPad

By PDFwarp · · 7 min read

Sign a PDF on iPhone or iPad with Markup in under a minute: share, Markup, +, Signature, Done. No printer or extra app needed.

Sign a PDF on an iPhone or iPad with Markup, which is already on the device. Open the PDF, tap the share icon, tap Markup, tap +, tap Signature, place it, then tap Done. There is no PDFwarp sign button. The PDF Editor edits text. It does not sign a file, and it does not move a signature image.

You do not need a printer, a scanner, or a paid signing service. A lease, a quote, or an NDA in Mail can be signed on the phone you already have.

Sign with Markup

The steps are the same on iPhone and iPad. An Apple Pencil only changes how you draw. It is not required.

1. Open the PDF — from Mail (tap the attachment), Files, Messages, or directly from any app that handed it to you.

2. Tap the share icon (the box with an upward arrow).

3. Tap Markup. If you do not see Markup, scroll the action list horizontally — it is often hidden behind a few other actions.

4. Tap the plus icon (+) in the bottom right.

5. Tap Signature.

6. If you have not saved a signature before, you will get a blank pad. Sign with your finger or an Apple Pencil. Tap Done.

7. The signature lands as a draggable object. Position it where it needs to go and resize using the handles at each corner.

8. Tap Done in the top-left. Choose Save File To... or send directly via the share sheet.

The signature is saved on the device for future use — every PDF you open from now on shows your existing signature as a one-tap option.

When You Need More Than a Hand-Drawn Signature

The hand-drawn Markup signature is fine for most agreements, but a few situations push you past what the built-in tools do well.

Typed signatures with a specific font. Markup only does hand-drawn. If you need a typed signature (some legal teams prefer this for clarity), use the Text tool (+ → Text) to add a typed name. iOS includes "Snell Roundhand" which looks reasonable for typed signatures.

Filling form fields, not just adding a signature. Many PDFs from HR, accounting, or government departments are actual fillable forms — tap a field and you can type into it without Markup. If the form fields do not work in your viewer, the PDF was probably exported as a flat image and you will need to add text on top with Markup instead.

Initials on every page of a multi-page document. Markup signs one page at a time. For a 30-page lease with initials required on every page, this gets tedious. The workaround: sign and initial the first page, save, then use the same Markup workflow on each subsequent page — your saved signature appears as a one-tap option on every page, so you place the saved one instead of drawing again.

Multiple signers. Markup is for you. If the PDF needs to be passed between three signers, each adding their own signature on different pages, every signer just runs through Markup separately and forwards the file. iOS does not have a built-in workflow for sequential routing — but for most informal multi-signer agreements, "sign and email back" handles it.

When the Signed PDF Is Too Large to Email Back

Marked-up PDFs sometimes balloon in file size — adding a high-resolution signature image to every page of a multi-page scan can push a 5 MB file to 30 MB. If the recipient's email rejects your signed copy, run it through Compress PDF at Medium quality. Compressing a signed lease or contract typically takes the file from 25-30 MB back down to 3-5 MB without affecting signature readability.

This is the most common reason "I signed it but it would not send" happens. The fix takes 10 seconds.

When the PDF Is a Scan and the Signature Lands in the Wrong Place

Scanned PDFs (the ones that look like photographs of pages rather than crisp digital text) sometimes have weird page geometry — slightly rotated, scaled inconsistently, with margins that fool Markup's positioning. The signature lands at the right spot in Markup, but when the recipient opens it, the signature sits in the margin or on top of body text.

When this happens, stay in Markup. Drag the signature onto the line, use the corner handles to resize it, and tap Done only when it sits where you want it. If it is still wrong after you save, open the saved file and run Markup again. PDFwarp's PDF Editor changes text boxes. It does not place or move a signature, so it is not a signing step.

What About Apple's "Sign and Fill" Banner on Newer iOS?

Recent iOS versions (17 and later) sometimes show a banner above PDFs in Mail asking "Sign and send back?" with a one-tap workflow. This works for simple single-signature cases when the banner appears. The catch: it only appears for PDFs Apple has identified as obviously signable (typically forms with clear signature fields). For a flat scan or an unusual PDF, the banner does not show and you fall back to Markup.

If you see the banner, use it. If not, Markup is the path.

Saving and Reusing Your Signature

The signature you draw in Markup the first time is saved on your device and synced across your Apple devices through iCloud. This means:

For most people this is convenient, not a security risk — a handwritten signature is not particularly secret, and the consequences of someone copying it from your saved signature are similar to the consequences of someone scanning any signed document you sent. But if you are signing legally significant documents on a shared device, delete the saved signature when you are done.

Combining a Signed Page With the Rest of a Document

Sometimes you only need to sign one page of a larger document and combine it back with the rest — for example, signing a signature page that came as a separate attachment from a larger contract. To combine the signed signature page with the rest of the document, use Merge PDFs — drag the unsigned pages and the signed signature page into the order you want, click Merge, download the combined file.

This is the workflow that closes the loop when someone sends you "the contract" and "the signature page" as separate PDFs.

What If You Need to Sign a Paper Document Instead?

If what you actually need to sign is a paper form — not a PDF that arrived by email — start by getting it into PDF form. iOS has a built-in document scanner in the Files app and the Notes app: open Files, tap the three-dot menu, choose Scan Documents. The result is a clean, edge-detected, perspective-corrected PDF that you can sign with Markup using the same workflow above.

For more on the photo-or-scan-to-PDF step, see our guide on turning iPhone photos into a PDF, which covers HEIC handling, page ordering, and when to use the proper scanner mode over a regular photo.

Privacy

Your signature is sensitive. PDFwarp processes uploaded PDFs ephemerally and deletes them immediately after your download — files are not stored, indexed, or shared with third parties. See the Privacy Policy for the full data flow. If you are signing a particularly sensitive document and want to avoid any third-party servers entirely, the iOS Markup workflow happens locally on your device — no upload required.

For documents containing extremely sensitive data (medical records, financial settlements, immigration paperwork), use the iOS-only path and skip the cloud tools entirely.

The Bottom Line

Signing a PDF on iPhone or iPad is built in — Markup in the Files or Mail app handles every casual signing situation in under a minute. Save your signature once, reuse it forever.

When Markup is awkward, the fixes stay specific. Compress PDF is for a signed file that email will not accept. Merge PDFs is for joining a signed page to the rest of a document. Neither one draws the signature. Markup does that, on the device.

For routine agreements — leases, NDAs, contractor quotes, school forms — you do not need DocuSign or Adobe Sign. iOS already has what you need.