I remember visiting a university in 1985 (very old), I see splendor and computer magic: a CRT screen simulated with a program that was part of a reorganization program.
Because typing consisted of “drawings”, long distances of a very small column, a person who could copy can easily see a long text this way.
Computers come from far away, but that direction remains the same. You can end up with a lot of more convenient functions, such as long text typing, long menus, or a variety of palettes, or something that puts it neatly in large concrete from top to bottom to be viewed, such as rearranged windows.
In the past, you had to rely on drivers or software a third person to rotate the monitoring screen, but Apple added to its Mac-based programs long ago. It's not really hidden, or it may be, maybe for a while, but it could be something you never thought of.
Some monitors also include a pivot integrated where the screen meets. I remember a few years ago I went around a bit that I didn't know it had a combination and I think I broke it for a while.
In most cases, you should be able to open the screen preferences panel and when macOS supports rotation monitoring, the rotation or rotation menu appears in the ‘Screen' tab, with options that may vary depending on the macOS type and display features.
Apple secretly points out, “If you do not see the pop-up menu, your computer does not support this feature.” It doesn't keep a list of what Macs have or don't have. It seems that iMacs do not support traditional rotation.
In previous versions of Mac OS X and MacOS, you may need to open ‘System Preferences' and hold down ‘Command' and ‘Option', click the ‘Show' item to force the menu to pop up.