# Password-Protect a PDF

Lock a PDF so it only opens with your password, before you email it or send it with a link. Choose whether people who open it may print, copy or edit it.

_Source: https://sharelargefilesfree.com/tools/protect-pdf · Updated 2026-09-29_

**Quick answer:** To password-protect a PDF, choose it, type a password twice and press Protect PDF. It is encrypted with AES-256, the strongest standard PDF encryption, which every current PDF reader supports; you can also block printing, copying or editing. The PDF and password never leave your device.

## How to use it

1. Choose one or more PDFs.
2. Type the password that will be needed to open them, twice.
3. Untick printing, copying or editing if you want to restrict them.
4. Press Protect PDF, then send the file and share the password separately.

## Open password and restrictions

- **Open password**: without it the PDF cannot be opened or read at all. The content is encrypted with AES-256 (PDF 2.0 security), supported by Adobe Acrobat and Reader, Chrome, Edge, Safari, Preview and phone PDF apps.
- **Restrictions** (printing, copying, editing): honoured by standard PDF readers once the file is open. They are a polite request more than a lock, because some programs ignore them; for truly confidential files rely on the open password.

## Choosing and sharing the password

Use a long password, such as three or four random words, and never send it in the same email or chat as the PDF. Send the file by email or with a [download link](https://sharelargefilesfree.com/), and the password by text message or phone. There is no way to recover a forgotten password, so keep an unprotected copy of the original.

## Encrypted on your device

Encryption runs in your browser with QPDF, a long-established open-source PDF library, compiled to WebAssembly. Neither the PDF nor the password is uploaded. To remove a password later, use [Unlock PDF](https://sharelargefilesfree.com/tools/unlock-pdf) with the password.

## Frequently asked questions

### How do I put a password on a PDF for free?

Choose the PDF here, type a password twice and press Protect PDF. The encrypted copy opens only with that password.

### How strong is the protection?

The open password uses AES-256, the strongest standard PDF encryption; its real strength is your password, so use a long one.

### Can I stop people printing or copying?

Yes, untick those options. Standard PDF readers honour them, but they are not a hard guarantee.

### Is my PDF or password uploaded?

No. Both stay on your device.

### I forgot the password. Can you remove it?

No. AES-256 cannot be undone without the password, which is the point; Unlock PDF only works when you know it.