On Mac, how to force log out but ensure app data saved first

Curious - “under the hood” how to every 15 min ask for user name & password, where if wrong, person is logged out - (not just lock screen where app still runs) - and crucially - where app data is saved before log out. Do we need to pray the app has what’s called an ‘API’ to direct a save?

Thanks so much. Please go easy on me, just a curious nube who wants to learn more.