How to Password Protect a PDF on iPhone

The Files app and Markup can't add a password to a PDF on an iPhone. File Acture's Protect PDF encrypts a PDF with AES-256 on the device: type a password twice, choose whether printing, copying and editing are allowed, and it saves a protected copy that asks for the password in any PDF reader.

Updated October 31, 20263 min read

By the File Acture team

A payslip, a passport scan, a contract with bank details: some PDFs should not be readable by whoever happens to get the email. A password on the file itself protects it wherever it goes. Here is what the iPhone offers, why it falls short, and how to protect a PDF in a few taps.

Can you put a password on a PDF on iPhone without an app?

No. The Files app can compress, rename and mark up a PDF, but it has no password option, and Markup doesn't either. Locking a note in Notes hides an attachment on your own phone, but the PDF you share from it is not protected.

What you want is encryption inside the PDF itself, so the file asks for the password on any phone or computer that opens it.

How to password protect a PDF with File Acture

Open Protect PDF and tap Add from Files to pick the PDF, or share it to File Acture from Mail or Files. Under Password, type the password in Password and again in Confirm password.

Under Permissions, choose what people who open the file may do: Allow printing, Allow copying text and images and Allow editing. Tap Protect.

The protected PDF is saved in On My iPhone › File Acture › PDF, ready to share. The original is not changed, and File Acture never stores the password you typed.

How strong is the protection?

File Acture encrypts the PDF with AES-256, the strongest encryption the PDF format offers. Without the password, the pages can't be read.

The permissions are a different kind of limit: a PDF reader is asked to respect them, and most do, but they are not a lock in the same way the password is. For a document nobody else should read, the password is what counts.

Use a long password: a short sentence is easier to remember and much harder to guess than a short word.
Send it separately: share the password by message or phone call, not in the same email as the file.
Keep a copy of it: a forgotten password can't be recovered by File Acture or anyone else.

How to remove the password later

To make an open copy again, use Unlock PDF with the password you know. A PDF that is protected has to be unlocked before tools such as Merge PDFs can work with it.

Is it safe to protect a PDF online?

To add a password online you upload the very document you are trying to protect, readable, to someone else's server. File Acture encrypts on the iPhone. The free version protects up to 5 PDFs per run, 5 runs a day; Pro removes the limits. To sign the document first, see how to sign a PDF on iPhone.