iPhone
Password protect a PDF on iPhone
Quick answer: on iOS 16 or later, open the PDF in the Files app, tap the file name at the top, choose Lock PDF, enter a password twice and tap Done. If Lock PDF isn't offered, or you want a separate encrypted copy to send, use this page in Safari: add the PDF, type a password twice and tap Protect. The download asks for that password whenever it is opened, and the file and password never leave your phone.
Steps last checked 19 October 2026 by the PDFWhisk team
At a glance
- Use this page to protect files quickly with a guided workflow.
- Accepted input: .pdf.
- Output: downloadable file generated in-browser for supported workflows.
- Upload Choose your file
- Process Runs locally
- Download Save result
Drop your file here
or tap to browse · accepts .pdf
Runs in your browser. No file uploads for supported tools.
Best on desktop for 100MB+ files · mobile recommended under ~100MB.
How local processing works
- Your PDF is processed in your browser using local JavaScript libraries.
- PDFWhisk does not upload your file to a processing server for supported tools.
- Only normal page assets load from the site (HTML/CSS/JS), not your document contents.
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Security & privacy detailsHow this tool helps
Secure your PDF documents with password protection. Set a password that must be entered to open and view the document. Perfect for protecting sensitive contracts, financial documents, personal records, or any file you want to keep confidential when sharing via email or cloud storage. The file is encrypted with AES-256. The password-protected PDF can be opened in any standard PDF reader that supports encryption. Since our tool processes everything in your browser, your original unprotected document and your chosen password never leave your device. Use it when you need to unlock pdf, sign pdf, compress pdf.
Best for
How it works
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1
Open this page in Safari on your iPhone
No app or account is needed. Save the PDF to Files first if it is in an email or a chat.
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2
Add the PDF
Tap the upload box and choose the PDF from Files.
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3
Enter a password twice
Use at least 4 characters; a longer passphrase is much harder to guess. Write it down somewhere safe, because it can't be recovered.
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4
Protect and download
Tap Protect PDF and download the encrypted copy. Open it from Files to check it asks for the password.
More files today? Free covers 3 tasks a day and files up to 50MB. For unlimited tasks and bigger files, Pro passes start at £1 for 24 hours. One-off payment, no subscription, and your files still stay on your device.
Locking a PDF on iPhone: what to know
Apple's Lock PDF and this tool both add an open password, so the PDF can't be read without it. The difference is where the protected file ends up.
How does Lock PDF in the Files app work?
Open the PDF in Files, tap the file name at the top of the screen and choose Lock PDF. Enter the password, confirm it and tap Done. It locks that file itself rather than making a copy, so keep an unlocked original elsewhere if you will need it.
When should I use the browser tool instead?
When Lock PDF isn't offered for that file, when you want to keep the original unlocked and send a protected copy, or when you want the same steps on a Windows PC or Android phone. The copy is encrypted with AES-256 and opens in Files, Adobe Acrobat Reader, Preview and browser PDF viewers once the password is entered.
Which password should I use?
A short phrase of three or four unrelated words is easier to type on a phone and much harder to guess than a short word with symbols. The tool needs at least 4 characters and does not store or recover passwords.
What else should I do before sending it?
If the file is too big for email or an upload form, compress it first and protect it last: compressing a protected file would need the password removed. To sign it as well, sign first, then protect.
Before you upload/share
- Open the PDF and check every page before you send or upload it.
- Keep the original files until the recipient or portal has accepted the document.
Frequently asked questions
Can I password protect a PDF on iPhone without an app?
Yes. On iOS 16 or later, open the PDF in Files, tap the file name at the top, choose Lock PDF, enter the password twice and tap Done. You can also use this page in Safari, which makes an encrypted copy.
Why can't I see Lock PDF?
Lock PDF needs iOS 16 or later and is not shown for every file location. Move the PDF to On My iPhone and try again, or use the tool on this page, which works in Safari whatever the file's location.
How strong is the protection?
This tool encrypts the PDF with AES-256 and sets one password that is needed to open it. A short or common password can still be guessed, so use a long one.
How do I tell the other person the password?
Send it a different way from the file, for example by text message or a phone call if you emailed the PDF.
Is my PDF or password uploaded?
No. Safari encrypts the file on your phone. The password is used only in the page and is never sent to PDFWhisk.
Can I remove the password later?
Yes, if you know it: use Unlock PDF, enter the current password and download a copy without it. A forgotten password cannot be recovered.
What to do next
Chain tools together for a complete workflow.
Popular searches for this tool
Intent-specific pages for common real-world tasks (upload limits, email attachments, iPhone workflows, and privacy-first processing).