Signing a PDF on iPhone takes about 30 seconds once you know where Apple hid the feature. No printing. No scanning. No emailing back to yourself. The signing tool lives inside the Markup interface, which works in Files, Mail and Safari. Most people never discover it.
Once you sign your first PDF on iPhone, the old print-sign-scan workflow stops making sense. Here is the practical walkthrough across the main ways you encounter PDFs on iPhone.
Signing a PDF in the Files App
The Files app is where most PDFs end up if you save them from email or web. Open Files and tap the PDF you want to sign. The PDF opens in the built-in viewer.
Tap the Markup icon at the top of the screen. It looks like a pen tip inside a circle. The Markup toolbar appears at the bottom. Tap the plus sign at the bottom right and pick Signature from the menu that pops up. The first time you use this, you draw your signature with a finger on the blank space provided. After that, your signature is saved and shows up every time.
Tap Done after drawing. Your signature appears on the PDF as a draggable image. Move it where you want. Resize by pinching. Tap Done again to save the signed version.
Signing a PDF from Email
If someone emailed you a PDF that needs signing, you can do it right inside Mail without saving the file first. Open the email with the PDF attachment. Tap the PDF to open it inside Mail’s preview. Tap the Markup icon at the top right.
The same Markup tools work here. Tap plus, pick Signature, drop it on the page, drag to position. When you tap Done, Mail asks if you want to Reply with the signed PDF attached. Tap Reply and send it back. The whole flow takes under a minute and saves the back-and-forth of saving, opening another app and re-attaching.
Signing from Safari or Web
For PDFs you find on a website, tap the link to open it in Safari. Use the Share icon at the bottom and pick either Markup or Save to Files. Markup opens the PDF in the same signing interface you use elsewhere. Save to Files lets you sign it later from the Files app.
Saving and Reusing Your Signature
iPhone remembers your signature after you draw it once. The next time you tap Signature in Markup, your saved one appears at the top of the panel. You can add multiple signatures, like one for your full name and another for your initials. Tap the plus sign in the Signature menu to add new ones. Tap an existing signature to edit or delete it.
For Documents That Need Real Legal Signing
Markup signatures are fine for most everyday forms. Permission slips. Soft contracts. Informal agreements. For anything legally binding (employment contracts, real estate documents, NDAs), use a dedicated e-signature service that adds audit trails and identity verification.
The major options worth knowing include DocuSign as the industry standard with strict identity verification, Adobe Sign with similar authentication levels, HelloSign or Dropbox Sign as more affordable options with free tiers for occasional use, and PandaDoc and Signaturit as alternatives for specific industries. These services add IP logs, timestamps and verified email addresses that make the signed document legally binding in most US jurisdictions.
Filling Form Fields
Some PDFs have proper form fields. Tap each field to type into it. iPhone detects these automatically if the PDF is set up correctly. For PDFs without proper fields, use the Markup text tool. Tap the plus icon and pick Text. A text box appears that you can drag and resize wherever you need to type on the document.
Adding Date and Initials
For forms that need a date next to your signature, use the Markup text tool to type the current date. Some users save their initials as a separate signature in Markup. This makes filling out long forms that need initials on every page much faster. Tap Signature, pick your initials, drop them on each page where needed.
Exporting the Signed PDF
After signing, tap the Share icon to send the signed PDF wherever it needs to go. You can save back to Files, send via Mail, send via Messages or upload to Google Drive, Dropbox or any cloud service connected to iPhone. The original PDF stays untouched unless you specifically overwrite it. Always good to keep the original as a backup.
Final Thoughts
To sign a PDF on iPhone, open it in Files or Mail, tap Markup, tap plus and pick Signature. Sign with your finger or Apple Pencil. Drag the signature to the right spot. Send it back via email or save to Files. For legally binding contracts, use DocuSign or Adobe Sign instead. Once you do this once, the printing-scanning-signing routine never makes sense again.
If you have a workflow for signing many documents quickly on iPhone, share it in the comments.