windows

Did you use bootcamp?

Try this:

How to switch between Windows and macOS:

Restart PC, then press and hold the Option (or Alt) ⌥ key during startup to switch between Windows and macOS.

Also You can read this:

Install Windows 10 on your Mac with Boot Camp Assistant - Apple Support

Restart your Mac in macOS or Windows - Apple Support

MS Windows need to run in Boot Camp or in a Virtual machine like Parallels.