PDF user password can prevent unauthorized persons from reading and viewing the PDF files, the owner password can block access to certain manipulations of the PDF document, such as editing, copying, printing and changing the PDF document. Most PDF files creators are likely set passwords to protect them. Forgetting or losing PDF password is probably one of the most annoying things that can happen to us when we can't open the password protected PDF files. Due to bad memory or some other reasons, we may lose PDF password and be rejected to get access to PDF document files.