iOS does not have a built-in way to password-protect a PDF, but you can do it for free in Safari — no app download, no cloud upload. Here is how to encrypt a PDF directly on your iPhone.
On your iPhone, open Safari and navigate to pdfeditor.onl/protect-pdf. The page is fully mobile-optimized.
Tap the upload area. iOS will ask where to pick the file — choose Files, iCloud Drive, or your Downloads folder. Tap the PDF to upload it.
Tip: If the PDF is in your Photos as a scanned document, save it to Files first via the Share menu.
Type a strong password you will remember. The tool uses 128-bit RC4 encryption applied entirely in your browser — the file is never sent to any server.
Tap Encrypt & Download. iOS will prompt you to save it to Files or open it in another app. Save it to Files > iCloud Drive to access it across all your Apple devices.
Yes. The password encryption follows the PDF 1.7 standard and is compatible with Adobe Reader, Chrome, Edge, and any standard PDF viewer on any platform.
Yes. Use the Unlock PDF tool at pdfeditor.onl/unlock-pdf and enter the password to remove encryption.