Legitimate rom-hosting communities occasionally password-protect files to avoid automated takedown bots. In these cases, the password is usually the URL of the website where you found the link (e.g., vimm.net ).
Legitimate emulators are free and do not require you to pay or enter a mobile phone number for "activation". Psemu3 Password
Unlike open-source projects with transparent development, Psemu3 lacks technical documentation, and many report it fails to actually load commercial PS3 games. Why is there a "Psemu3 Password"? Psemu3 lacks technical documentation