MacOS provides a number of ways to back up your computer, but the simplest way to back up your entire computer is to use Time Machine.
To set up Time Machine, connect an external hard drive to your Mac.
Open System Preferences and click on Time Machine.
Select the “Use a hard drive” option and click on the “Select Disk” button.
Select the external hard drive you connected to your Mac and click on the “Use Disk” button.
Time Machine …