If you want to determine if your Mac is compatible for the newest version of macOS, then you should click on the Apple icon on the upper left corner of your screen and pick About This Mac. Make sure you know your Mac type and its release year because the level of compatibility differs among various types of MacBook Air, MacBook Pro, iMac, and Mac mini. You will have to go to System Settings and choose General > Software Update to find out what upgrades you can do to your computer.