PDF tool guide
How to use Protect PDF online
Add an AES-256 opening password to a new PDF copy.
Step-by-step
Use Protect PDF in three quick steps
- Choose an unlocked PDF up to 25 MB and 80 pages.
- Enter a new password of at least eight characters and confirm it.
- Download the protected copy, then test that the chosen password opens it.
What to check in the result
Unlocked PDFs up to 25 MB and 80 pages. Use at least eight password characters. Keep the password safe; modifying a signed file can invalidate its signature.
Keep the source and password. This adds AES-256 encryption requiring a password to open the copy; it does not create a digital signature or recipient audit trail. No. Keep your password somewhere safe. Modifying a signed document can invalidate its signature.
Keep the original and inspect the downloaded copy before sharing it or replacing your source file.
Before you begin
Keep your original file as a backup and only process content you are authorised to modify. If you are signed in, open My account to review completed tool usage and any active membership dates.