Check the box that says Automatically keep my Mac up to date.Open the Software Updatepage in the System Preferences.It’s a good idea to tell your Mac to update macOS automatically, so you never need to worry about missing an important update. How to set your Mac to automatically update macOS When the update is downloaded, your Mac will prompt you to Restart so it can install the update. Note from our experts: It could take anywhere between five minutes and five hours to download and install a new software update for your Mac, depending on the size of the update and the speed of your internet connection. If the update is already downloaded, click Restart Now to install it instead.Click Upgrade Now to download and install that update The System will search for new macOS updates, and you’ll need to wait a short while
It’s important to regularly check for and install software updates on your Mac.