The menu bar belongs to the app, not the window
On a Mac the menus live at the top of the screen and always belong to whichever app you are using.
Published: · Source: Genius Manu
The single biggest change coming from Windows: menus are not inside the window. They sit in the strip across the top of the screen, and they always belong to the frontmost app. Click a different window and the whole bar changes with it.
The layout is the same everywhere: the app’s own name first, then File, Edit, View, Window and Help. If you cannot find a command, it is almost certainly in one of those five.
On the far left, the Apple menu is system-wide rather than app-specific. It is where About This Mac, System Settings, Sleep, Restart and Log Out live, and it never changes no matter which app is in front.
The right-hand end is the status area: Wi-Fi, battery, Control Centre, the clock, and an icon for any app that asks for one.
Related tips
Put the controls you use most in the menu bar
Bluetooth, AirDrop and the rest can sit permanently at the top right instead of two clicks deep.
Force quit an app that has stopped responding
The Mac equivalent of Ctrl+Alt+Delete for a single frozen app.
Set up right-click and tap-to-click on the trackpad
There is no second button, but there is a right click — and you can stop physically pressing the trackpad down.