Use About This Mac to check the version of Mac operating system installed, and find out whether it’s the latest (newest, most recent) version.
From the Apple menu (top left) in the corner of your screen, choose About This Mac. You should see the macOS name, such as macOS Ventura or macOS Monterey, followed by its version number. If you need to know the build number as well, click the version number to see it.
