Shortcut to make a window truly full screen in Windows

for apps that don't have a full screen mode at all, the nearest thing is turning on 'automatically hide the taskbar' in taskbar settings. maximise the window and it gets the whole screen except its own title bar.

F11. Works in every browser and File Explorer, press it again to come out. Win + Up arrow only maximises, which still leaves the taskbar and title bar. Some games and terminal apps use Alt+Enter instead.