How can I have an application menu like macOS?

Solution 1:

I know for a fact that Unity has it. It's slightly hidden though. It only shows when you are hovering your mouse over title bar.

Solution 2:

GNOME cannot do this.

Unity can and is still available in the 20.04 repositories. Or, you can try the free Ubuntu Unity remix -- https://ubuntuunity.org/

I am running this on 1 machine and it's pretty good. Not perfect but it works.

Alternatively, I believe that both MATE and KDE 5 can be customised to look and work in a Mac-like manner, with a global menu bar at the top of the screen and a dock for launching and switching apps along one screen edge. I have not tried this myself, though.

KDE: https://www.dedoimedo.com/computers/plasma-look-like-mac.html

MATE: http://mate-macos.blogspot.com/p/making-ubuntu-mate-look-like-macos.html

Of course both MATE and KDE have Ubuntu flavours.