The six-step version
Why "in Safari" matters
Most "sign PDF" results when you search from your iPhone push you toward installing an app — DocuSign, Adobe Fill & Sign, PDFelement, SignEasy. Some are free with limits. Some demand a signup. Some show ads. Some quietly upload your PDF to their servers for "processing."
The Unfuss signer is a single web page that loads pdf-lib (an MIT-licensed JavaScript library) into Safari and does the work right there on your iPhone. There's no servers, no account, no in-app purchase. Three practical benefits:
- Nothing to install. You're not adding another app to your home screen for a one-time task.
- The PDF stays on your phone. Sensitive document? Tax form? Contract? It never leaves your device.
- Works on any iPhone. iPhone SE, iPhone 16 Pro Max, iPad — anything that runs iOS 14 or later in Safari.
Apple Pencil tips
If you have an iPad and an Apple Pencil, signing with the Pencil produces a noticeably nicer signature because of pressure sensitivity and palm rejection. A few tips:
- Hold the iPad in landscape — gives you more horizontal room for a longer signature.
- Zoom the canvas in before you sign — Safari pinch-zoom works on the signature pad. Larger drawing = smoother result when scaled back down.
- If your signature looks shaky, try drawing it once big to "warm up," then redraw a final version. It's a real motor-memory effect, not a tool limitation.
Is it legally valid?
In short, yes — for most everyday agreements. Both ESIGN (US, 2000) and eIDAS (EU, 2014) recognise drawn or typed electronic signatures on PDFs as valid signatures for ordinary contracts: leases, freelance invoices, school permission slips, gym waivers, NDAs between small parties.
Where a basic visual signature isn't enough: court-admissible signatures with identity verification, signatures on property deeds (in some jurisdictions), signatures on wills, signatures on government forms that explicitly require a "qualified" e-signature. For those, use a service like DocuSign or Adobe Sign that provides identity verification, an audit trail, and a tamper-evident certificate. Unfuss doesn't try to compete with those — it solves the everyday case where someone just needs to see your signature on the line.
Frequently asked
Can I sign a PDF on iPhone without downloading an app?
Yes — three ways. (1) Apple's built-in Markup tool in Mail/Files supports signature drawing. (2) Files app → tap-and-hold a PDF → Markup. (3) The Unfuss signer in Safari, which works in any browser and supports both drawn and typed signatures with positionable drag handles.
Does it work with Apple Pencil?
Yes. The signature canvas accepts pointer input from finger, Apple Pencil, or any stylus. Apple Pencil generally produces a smoother signature because of pressure sensitivity.
Is a signed PDF from an iPhone legally binding?
For most everyday agreements, yes — ESIGN (US) and eIDAS (EU) recognise visual electronic signatures on PDFs. For court-admissible signatures with identity verification, use DocuSign, Adobe Sign, or a similar qualified provider.
Is the PDF uploaded somewhere to be signed?
No. The signer runs in Safari on your iPhone using JavaScript. The PDF is parsed locally by pdf-lib, the signature is composited on, and the result is saved back to Files. Nothing is transmitted. You can verify this in Safari Web Inspector — no upload requests appear.
Can I add the date next to my signature?
Yes. The signer has a "Add date" text option you can drop anywhere on the page alongside the signature.
How do I send the signed PDF back to whoever asked?
After downloading, open Files → tap-and-hold the signed PDF → Share → choose Mail, Messages, AirDrop, or whichever app you originally received it through.
What's the difference between a drawn and a typed signature?
Visually, drawn looks like a "real" signature; typed (in a handwritten-style font) looks like a stylised version of your name. Both have the same legal weight under ESIGN/eIDAS for everyday agreements. Use whichever the receiving party seems to expect — most accept either.