Free Keylogger Pro doesn't offer the possibility to see other users because it captures everything it sees on the screen regardless of locked users, Windows, visited websites or installed antivirus programs.
There is no need to configure it for each individual user, but if you want, you can install it. I know that Windows will give you an error if you try to do this saying it's already installed.
Reinstall the program if you want and select All Users, and the software will monitor everyone.
Note: You should also display a message for users to know that they are monitored.