Document security

How to Password Protect a PDF

Password protection adds an encryption layer to a PDF before you send or store it. PDFmuto performs the operation in your browser, so the document bytes stay on your device.

Last updated: 2026-08-27

Steps

  1. Open Protect PDF

    Choose Password Protect PDF and add the document.

  2. Set and confirm a password

    Enter a password that the intended recipient can receive securely.

  3. Choose encryption

    Use AES-256 for current readers, or RC4 only for older-reader compatibility.

  4. Download and test

    Download the protected PDF, open it, and verify the password prompt works.

Choose an encryption option

AES-256 provides the strongest option available in the tool and suits current PDF readers. RC4 exists for compatibility with older software and should be used only when necessary.

A password protects the file only if you share it through a separate trusted channel. Do not place the password in the same unprotected email as the PDF.

Test the protected copy

Open the downloaded PDF in a separate reader and enter the password. This confirms that the file opens before you send it.

Keep an unprotected original in a secure location if you may need to edit the document later.

Related tools

  • Remove PDF MetadataStrip the title, author, and other hidden data from a PDF.
  • Protect PDFAdd a password to a PDF with strong AES-256 encryption.
  • Unlock PDFRemove the password from a PDF you own, entirely in your browser.