macOS ships with a tool called softwareupdate to scan, list, download, and
install updates. If you're comfortable with typing in commands, you can see if
recommended updates are available:
$ sudo softwareupdate -l
The message No updates are available. will print at the end.
You can check for non-system updates from the App Store. From the Apple menu ()
click on App Store, followed by Updates on the sidebar. You should not see any
available updates.
You can check for system updates from System Preferences. From the Apple menu ()
click on System Preferences, followed by Software Update. You should see a
message that includes Your Mac is up to date.
You can install updates from the command line using the softwareupdate tool.
To install recommended updates with progress indication run:
sudo softwareupdate -ir --verbose
You can install non-system updates from the App Store. From the Apple menu ()
click on App Store, followed by Updates on the sidebar. You can install individual
updates by clicking Install or install all updates by clicking Install All.
You can install system updates from from System Preferences. From the Apple
menu () click on System Preferences, followed by Software Update. If any
updates are available, click the Update Now button to install them.