how do i check what os do i have
How do I check what MacOS program do I have?
iMac 21.5″, macOS 10.13
Question marked as
To get more information about your computer, choose: (Apple menu) > 'About This Mac' in the upper left corner of any window, then "More Info..." or "System Report". There's more about this in "About System Information [Profiler] on your Mac" - https://support.apple.com/HT203001