How to add a password
- Open Protect PDF and add your file.
- Enter a password twice and download the encrypted PDF.
- Test it: opening the file should now prompt for the password.
What the encryption protects
The document contents are encrypted with a key derived from your password, so the protection travels with the file wherever it goes — email, USB, cloud. The open password is strong protection; permission flags (like "no printing") are honoured by well-behaved viewers rather than enforced by maths.
Choosing a good password
- Use 12+ characters, not a name or "1234".
- Store it in a password manager — there is no recovery if you forget it.
- Keep an unprotected original somewhere safe.
Removing it later
If you need to take the password off a file you own, use Unlock PDF with the current password.
Private by design
Encryption happens in your browser — neither the file nor the password is ever uploaded.