Your landlord wants the lease signed before the office shuts. You're on the train. The iPhone in your pocket can absolutely sign that PDF — it's just that Apple's Markup signature tool is hidden three taps deep and doesn't always remember your scribble.
There's a faster way that works on any iPhone.
Markup works — until it doesn't
Apple's built-in signature lives inside Markup, inside Mail, inside the share sheet. You can use it. It saves your signature for next time. But if you receive a PDF outside Mail (Slack, Drive, WhatsApp), you bounce between apps until something opens it correctly.
Flint's signature tool skips all that. Open Safari, drop the PDF in, sign with your finger, download the signed copy. No app handoffs, no Mail-only restrictions.
Step-by-step on iPhone
Save the PDF to Files or hold it long enough in the message thread to get a Save to Files option. Open Safari, navigate to Flint's signer, and upload the file. The PDF appears full-width on the screen.
Tap where you want to sign. A signature pad pops up. Sign with your finger — or an Apple Pencil if you've got one paired to an iPad Mini. Tap Done, drag the signature into position, and hit download.
Multiple signatures, initials, dates
Leases and contracts ask for initials on every page and a full signature at the end. Flint lets you save the signature once and stamp it on as many pages as you need, plus type dates directly onto the page. If the PDF needs other edits before signing — like filling in your address — edit the PDF first, then sign in the same session.
FAQ
Is a finger-drawn signature legally valid?
In most jurisdictions, yes — under eIDAS in the EU/UK and ESIGN in the US, a clear intent to sign and a reproducible mark generally count. For higher-assurance signing (deeds, notarisation), you may need a qualified e-signature service. For everyday contracts, a drawn signature is fine.
Can I use an Apple Pencil to sign?
Yes — if you're on an iPad or iPad Mini with a Pencil paired, the signature pad accepts Pencil input. The line is smoother and looks more like your real signature than a finger drawing.
Where does the signed PDF save to?
Wherever you tell iOS to save it. The download usually goes to your Files app's Downloads folder, but you can use the share sheet to send it straight to Mail, Drive, or back to the original conversation.
If a PDF needs signing right now and your iPhone is the only thing you have, sign it in Safari. Two minutes start to finish.