How to Password-Protect a PDF on iPhone
Preview on the Mac has had an "Encrypt" checkbox for years. The iPhone doesn't — there's no Lock button in Files, Mail or Notes. This guide covers the two built-in workarounds that do exist, why they usually aren't enough, and the straightforward way to lock a PDF with a real open password.
The honest answer: iOS can't do it directly
Open a PDF in the Files app and look for "Lock", "Encrypt" or "Set Password" and you'll come up empty. Files can compress, duplicate, tag and mark up a PDF — but not encrypt one. Mail can't. The share sheet can't. Shortcuts has a "Make PDF" action but no encrypt action. It's one of a handful of things macOS does trivially that iOS simply doesn't ship.
Two things get suggested as workarounds. Both exist; both have a catch.
Workaround 1: Lock the note in Notes (locks the note, not the PDF)
- Attach the PDF to a note (share → Notes).
- Tap the ⋯ button → Lock, and confirm with Face ID or your passcode.
The note is now locked — on your devices. The PDF inside it isn't. The moment you share it, forward it, or save it to Files, it's an ordinary unlocked PDF. Fine if the goal is "nobody who picks up my phone can read this"; useless if the goal is "the recipient needs a password."
Workaround 2: Export from Pages with "Require Password" (images only)
Pages can export a PDF that asks for a password on opening. The catch is getting your document into Pages: on iPhone, Pages imports a PDF as a picture of its first page only, so it's no use for an existing multi-page PDF. It works if what you have is photos of pages.
- Open Pages, create a blank document, and insert your page photos — one per page.
- Tap ⋯ → Export → PDF.
- Turn on Require Password, enter and confirm a password, then tap Export.
- Share or save the PDF.
The result is a properly encrypted PDF. But you've spent five minutes in a word processor, the pages are photos rather than cleaned-up scans, and you'll do the whole dance again next time.
When you need an app
For an existing PDF, a scanned document, or anything you do more than once, you need a PDF tool that encrypts on the phone. Broadly, the options are:
- Adobe Acrobat Reader — "Protect" is a Premium feature behind a subscription.
- PDF Expert — password protection is in the paid tier, also a subscription.
- iLovePDF / Smallpdf — free-ish web tools, but they upload your PDF to a server to encrypt it, which is an odd thing to do to a file you're locking precisely because it's sensitive.
- Scaniva — $12.99 one-time Full Version, encryption happens on the device, no account.
Password-protect a PDF with Scaniva (4.5.0 or later)
- Open the document in Scaniva — a scan, an import from Files or Photos, or a PDF sent over with Open in Scaniva from Mail or Files.
- Tap Export, then Export with Password or Watermark…
- Under Password, enter a password and confirm it. Anyone opening the PDF will need it.
- Decide what the reader may do: switch Allow printing and Allow copying text on or off.
- Optional: add a watermark — type your own text or tap a preset (CONFIDENTIAL, COPY, DRAFT) and set the opacity. It's printed diagonally across every page.
- Tap Share PDF and send it via Mail, AirDrop, Files or Messages.
The recipient opens the file in any PDF reader — Preview, Acrobat, Chrome, Edge, the Files app — and gets a password prompt. Nothing to install on their end: this is standard PDF encryption, understood by every reader made in the last twenty years.
Send the password separately
Email the PDF; text the password. A password sitting in the same email as the attachment protects against nothing except an accidental double-click.
What a PDF password actually protects (and what it doesn't)
Worth being precise here, because "protected" means two different things inside a PDF:
- The open password is real encryption. Without it, the content is scrambled — no reader, mail server, cloud preview or search index can see the text or images. There's no back door: if you forget the password, that copy is gone. (Your original document in Scaniva is unaffected; the protected file is an export.)
- The print and copy permissions are a request, not a lock. Well-behaved readers — Preview, Acrobat, Chrome — honor them and grey out Print or Copy. A determined recipient who has the open password and the right tool can strip them. Treat "no printing" as a clear signal of intent, not a guarantee.
- A watermark is a visible deterrent. CONFIDENTIAL across every page won't stop a screenshot, but it makes plain that the document wasn't meant to be forwarded, and it survives printing and photocopying.
"Lock PDF" can also mean: lock the app
If what you actually want is that nobody who borrows your phone can browse your scans, that's a different feature. Scaniva has an app lock in Settings — Face ID or Touch ID is required to open the app. No password is applied to the files themselves; it's a lock on the front door, not on each document.
What it costs
Password protection, permissions and watermarks are part of Scaniva's Full Version — $12.99 one time, no subscription, no account. Free-version exports carry a small footer on each page. Encryption runs on your iPhone; the file never touches a server.
Lock it before it leaves your phone
Scan, sign, password-protect and watermark PDFs — all on-device. Free to try, $12.99 once for the Full Version.
Download on the App StoreFAQ
Can I password-protect a PDF on iPhone without an app?
Not directly. Files, Mail and the share sheet have no encrypt option. The only built-in route is Pages: build the document from page images and turn on Require Password when exporting to PDF. Locking a note in Notes protects the note on your device only; the PDF inside is unlocked the moment you share it.
How do I remove a password from a PDF on iPhone?
If you created the protected file in Scaniva, the original document in your library has no password — export it again without one. For a protected PDF from someone else, iOS has no built-in way to strip the password; on a Mac, open it in Preview with the password and export a copy without encryption, or use a PDF app with an unlock function on the iPhone.
Can I lock a PDF with Face ID instead of a password?
There's no Face ID inside the PDF format. Face ID can lock an app or a note on your own device — Scaniva has an app lock in Settings — but for a file you send to someone else, a password is the only lock that travels with the file.
Does a PDF password stop Gmail or iCloud from reading the attachment?
Yes. An open password encrypts the content, so mail servers, cloud previews and search indexes see an opaque file. Send the password through a different channel than the attachment — a text message, for example.
Can I add a watermark without a password?
Yes. On the protected-export screen, leave the password fields blank and add only the watermark. The PDF opens normally with CONFIDENTIAL, DRAFT, COPY or your own text printed diagonally across every page. If you also need it signed first, see how to sign a PDF on iPhone.