You can add a password to a PDF to limit access and restrict certain features, such as printing, copying and editing.
There are two kinds of passwords that could be applied to a PDF file: a Document Open password and a Permissions password. When you set a Document Open password, anyone who tries to open the PDF must type in the password that you specified. When you set a Permissions password, anyone who wants to change the restrictions must type the Permissions password. Please note that if a PDF is secured with both types of passwords, it can be opened with either password, but only the Permissions password allows you to change the restrictions.
Tips:
- There’s no way out to recover password from the PDF if you forgot it. To keep a backup copy of the PDF that isn’t password-protected is a good choice.
- Foxit PDF Editor allows you to input Unicode password in the password input box when you open a document protected by Unicode password.