1. Choose System Preferences from the Apple menu, then click Software Update to check for updates.
2. If any updates are available, click the Update Now button to install them. Or click “More info” to see details about each update and select specific updates to install. You might be asked to enter your administrator password.
3. When Software Update says that your Mac is up to date, the installed version of macOS and all of its apps are also up to date. That includes Safari, Music, Photos, Books, Messages, Mail, Calendar, and FaceTime.
4. To automatically install future updates, including for apps that you got from the App Store, select “Automatically keep my Mac up to date.” Your Mac will notify you when updates require it to restart, so you can always choose to install those later.