However, these tools will require you to provide the user password if the PDF is strongly encrypted, like AES 128 or AES 256 encryption. User Password: It is the name of the password that a user must use to access a password protected PDF file.
Owner Password: Also known as “change permissions password” is the name of the password that owner of the PDF document uses to restrict PDF editing features, such as copying, printing, commenting and other content edits. Fortunately, there are many third-party tools like Free PDF Password Remover (warning! malware has been reported in this one) that will let you remove the owner and user passwords (the former is used to restrict PDF editing while the latter is used to open a PDF). The ability to add a password with multiple tools also means that it can be quite frustrating to remove a password manually if you ever need to make the PDF file password free and accessible to others. It is very simple to password protect a PDF, you can easily add a password using Adobe’s own PDF editing tool or a third-party tool.