Instant PDF Password Remover is the free tool to instantly remove Password of any protected PDF file.
Note that it cannot help you to remove the unknown password. It will only help you to remove the known password so that you don't have to enter the password everytime while opening the PDF file.
It makes it even easier with the 'Right Click Context Menu' integration. This allows you to simply right-click on the PDF file and launch the tool. Also, you can Drag & Drop PDF file directly onto the GUI window to start the password removal operation instantly.