How to sign a PDF shared with you on Google Drive from your iPhone

Someone shared a PDF with you on Google Drive — a contract, a waiver, a supplier form — and it needs your signature. You open it in the Drive app on your iPhone, and at the bottom of the page there’s a button that looks like exactly what you want: Fill out form.

It isn’t.

That button fills interactive form fields — the text boxes, checkboxes and dropdowns a PDF was built with. It is documented by Google as form filling, and it does not do signatures. Tap it, type your name and address into the fields, then go hunting for a signature option and there is nothing there. The Drive app on iOS has no Markup, no pen, no signature tool at all. Half the time the button isn’t even offered, because the PDF has no interactive fields to fill.

So the file has to leave Drive before you can sign it. That’s the whole trick, and it takes about fifteen seconds.

The free route: get the PDF into Files, then use Markup

Apple’s Markup can sign this document properly and costs nothing. It just can’t reach a file that lives inside Drive’s viewer.

1. Open the PDF in the Google Drive app.
2. Tap the ⋮ (More) button — top right in the preview, or beside the file in a list.
3. Tap Open in (some file types show Send a copy instead — either lands you at the same iOS share sheet).
4. Choose Save to Files and pick somewhere you’ll find again — On My iPhone → Downloads is fine.
5. Open the Files app and tap the PDF.
6. Tap the Markup icon (the pen tip, top right).
7. Tap + → Signature. Draw one with your finger, or pick a signature you’ve saved before.
8. Drag it onto the signature line, resize it with the corner handles, and add the date as a Text box if the form asks for one.
9. Tap Done, then the share icon → Save.

That’s the complete free answer — no app, no account, no upload. If this is a once-a-year job, stop here; Markup is genuinely enough.

A faster variant, once you know it: at step 3 you can send the PDF straight into a signing app from the same share sheet and skip Files entirely. Saving to Files is the route worth writing down because it always works; the share sheet is the one you’ll use after the first time.

The trap nobody mentions: your signed file is a new file

This is the part that catches people out, and it has nothing to do with signing.

The moment you tapped Open in, you made a copy. It is on your iPhone. It is not the document in Drive, and nothing you do to it will appear in the shared file — the sender will still be looking at the blank original.

If the file was shared with you view-only (or Commenter), that’s the end of the road for editing in place. There is no way to write a signature back into someone else’s Drive file from an iPhone, and you shouldn’t try. Return it instead:

• Attach the signed PDF to a reply — email it back from Files, which is what most senders actually want. Rename it contract-signed.pdf first so nobody opens the wrong one.
• Upload it to Drive as a separate file and share that with the sender, if that’s how they work.
• Ask for Editor access only if the sender specifically wants the original file updated — and even then, you’d be uploading a new version, not annotating theirs.

One more thing worth checking early: if the owner turned off downloading for viewers, the Open in and Send a copy options disappear altogether. That isn’t a bug on your end and there’s no workaround from the phone — ask the sender to email you the PDF, or to allow viewers to download. If it does arrive as an email attachment instead, signing it from Gmail has its own detour, and Apple Mail is the easy case.

What about opening Drive from inside the Files app?

Drive can appear as a location in Files → Browse, and you can open the PDF and mark it up from there. It’s tempting because it looks like you’re editing in place.

Be careful with it. Markup will try to save back through Drive, which fails on a file you only have view access to, and can leave you unsure whether your signature was written anywhere at all. The copy-then-return route above is slower to describe and much easier to be certain about. If you do use the Files route, close the file and reopen it afterwards to confirm the signature is really in the document.

If it’s a Google Doc rather than a PDF

Different job. A Doc has no signature tool on iOS either, but the fix is to export it to PDF first — that flow is here. And if the PDF genuinely does have interactive fields you need to complete as well as sign, filling and signing a form on iPhone covers the field-by-field part.

Where the free route starts costing you time

Markup is fine occasionally. It grates when signing becomes routine, and always in the same places: the signature is a raw finger-drawing, so a version you like takes several attempts on glass every single time; the date, your printed name and your initials are separate text boxes you create and nudge by hand; and a ten-page agreement wanting initials in every corner is ten placements, each one drawn slightly differently.

Doing it in Signed

Signed picks the file up at the same Drive share sheet, so the detour collapses:

1. In Drive, tap the PDF → ⋮ → Open in → Signed.
2. Tap your saved signature and drop it on the line. You create it once — drawn properly, typed in a real handwriting style, or generated from your name — and it’s identical on every document afterwards.
3. Add the date, initials, printed name or a checkmark from the same tray, one tap each.
4. Tap Finish for a clean, flattened PDF, then share it back — as an email attachment, or uploaded to Drive as a new file.

There’s no Google Drive integration or account connection involved, and there shouldn’t be: the PDF arrives through the standard iOS share sheet like any other file, and it never leaves your iPhone. A document you were trusted with doesn’t need a third copy on somebody else’s server.

Quick answers to the related questions

Can I sign it without making a copy? No. Nothing on iOS can annotate a PDF while it’s sitting in Drive’s viewer — a copy has to exist somewhere, either in Files or in a signing app.

I tapped Fill out form and typed everything, then lost it. Tap Save at the top right before you leave — that writes the field values back to the Drive file. It still won’t add a signature; you’ll need the copy-out route for that.

Will the sender see my signature as a comment? Not if you export properly. Markup’s Save writes a normal annotated PDF; Signed exports a flattened copy where the signature is part of the page. Either opens the same way on any device — worth flattening before you send if the document is going anywhere official.

The PDF asks for a password. Then that comes first — signing a password-protected PDF is a separate step.

Two of us need to sign it. Sign, return, let the other person sign the returned copy — the order matters.

One honest note

Signed is a signing tool, not legal advice. For the everyday paperwork that gets shared on Drive — NDAs, freelance contracts, school forms, supplier agreements — a signed PDF sent back is simply how it’s done. For documents with real legal weight, like a will, a power of attorney or a property deed, a notary or witnesses may be required depending on where you are, and signing on a phone doesn’t change that. Check what your document actually needs before you return it.

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Related: How to sign a PDF attachment in the Gmail app on iPhone · How to sign a Google Doc on iPhone · How to fill out and sign a form on iPhone · Free signature generator