01
Open your PDF
Choose it from Mail or Files.
The quick version
Open the PDF from Mail or Files, sign on your iPhone, then send it back. If the recipient sees a blank signature, the PDF may need to be flattened first.
The free way: Apple Markup
iPhone already has a signing tool. Apple calls it filling out forms, signing documents, and creating signatures, and it lives inside Markup. Tap the PDF attachment in Mail, tap the Markup (pen) icon, tap +, then Add Signature. Draw it, drag it into place, tap Done, and Mail offers to reply with the marked-up file.
For a one-page permission slip going to someone else on an iPhone or Mac, that's genuinely enough. You don't need to buy anything.
Why the signature sometimes disappears
Markup places your signature on top of the PDF as an annotation. Apple apps show it, but some Windows and Android viewers don't. The person you sent it to may see a blank signature line.
To avoid that, flatten the PDF so the signature becomes part of the page. The file then looks the same when it's opened in Acrobat, Edge, Chrome, or on Android.
Markup also has no real date field, checkbox, or initials tool. You can type text boxes, but lining them up across a 12-page lease on a phone screen is slow.
When Markup isn't enough
Need the signature to show up on their screen?
If the person opening your PDF uses Windows or Android—or the form needs dates and initials—eSign PDF flattens everything into the page before you send it back.
Sign a PDFFirst export free. Then $59.99 once in the US. No account.
How to sign a PDF on iPhone with eSign PDF
1
Open the PDF in eSign PDF
In Mail, tap the PDF attachment, tap the Share button, and choose eSign PDF. From Files, Safari, or Messages it's the same Share Sheet. Paper-only document? Scan it with the camera inside the app.
2
Sign and fill
Draw your signature with your finger (or type it, or import a photo of your pen signature). Tap to place it on each signature line. Add the date, initials, and checkboxes where the form asks for them. The app highlights likely signature and date fields for you.
3
Flatten and export
Tap export. eSign PDF flattens the file, so the signature and fields become part of the page and show up on any device.
4
Send it back
Share straight to Mail, Messages, AirDrop, or Files. Reply to the original email with the signed PDF attached. Done.
Once it's signed and flattened, share it straight back from Mail, Messages, or Files.
Open your PDF. Add your signature. Send it back.Mistakes that make people re-sign
- ✕Printing, signing with a pen, and sending a phone photo of the page. It's crooked, hard to read, and often rejected.
- ✕Sending an unflattened Markup file to someone on Windows or Android — they see a blank signature line.
- ✕Signing page 1 and missing the initials on pages 2–9 of a lease.
- ✕Forgetting the date next to the signature when the form asks for one.
- ✕Uploading a lease or W-9 with your Social Security number to a random website to sign it.
Is signing on your phone legally valid?
For most everyday US documents — like leases, NDAs, offer letters, school forms, and W-9s — an electronic signature generally counts. Some documents have special rules, including wills and certain court filings. If the sender requires a specific signing platform, use theirs.
What it costs
Apple Markup: free. eSign PDF: $59.99 one-time (US), no subscription needed, no account. For comparison, DocuSign Personal: $11/month billed annually ($132/year), 5 envelopes/month — built for people who send documents, not people who receive them.
FAQ
Can I sign a PDF on iPhone without printing?+
Yes. Open the PDF from Mail or Files, sign it with Markup or a signing app, and send it back. No printer or scanner needed.
Why doesn't my Markup signature show on Windows or Android?+
Markup saves your signature as an annotation layer, and some non-Apple viewers don't display it. Flatten the PDF so the signature becomes part of the page. eSign PDF flattens on export.
Do I need DocuSign if I only need to sign?+
No. DocuSign is for sending documents to other people to sign. If you received a PDF and just need to sign and return it, you don't need an account there. DocuSign Personal: $11/month billed annually ($132/year), 5 envelopes/month.
Does eSign PDF upload my document?+
No. Signing and flattening happen on your iPhone. There's no account and it works offline.
How much does eSign PDF cost in the US?+
$59.99 one-time (US). Other plans and local prices are shown in the App Store.
Sources
- Apple iPhone User Guide: Fill out forms, sign documents, and create signatures
- Apple Community: Markup edits not showing on non-Apple devices
- MacRumors Forums: flattening PDFs so signatures show in Acrobat
- 15 U.S.C. § 7001 — Electronic Signatures in Global and National Commerce Act (ESIGN)
- DocuSign eSignature plans and pricing