The software used to create and edit PanelView Plus terminals has a security subsystem that is tied to the editing computer; it's called "FactoryTalk Security" and the computer has all the usernames and passwords saved in it.
When you create proper backup Archives, you use a "Application Manager" utility that wraps up the application, the communication settings, and the security information from the computer that was used to make the application. You can later "restore" that Archive file to a different computer and the usernames and passwords should come with it.
Because FactoryTalk is similar to the Windows security system, it doesn't show you the passwords. Even when you back up the security information, the passwords are always hidden. They should be able to be reset by a user who has Administrative access, but they cannot be "shown".
90% of the time the FactoryTalk administrator password is the same as the Windows administrator password because the user has simply chosen to allow FactoryTalk to inherit the Windows Administrator credentials.