FACTORY RESET
Before you dispose of any Mac, it’s vital to remove from it all trace of personal data, which isn’t too difficult on most Intel Macs just by formatting the internal storage. But this becomes more complex if the Mac has a T2 chip or is an Apple silicon model.
The new command to Erase All Content and Settings, available in the System Preferences menu, is an excellent and reliable way to do that, as it destroys all the encryption keys stored on that Mac, making access to old data impossible. It also wipes all volumes on internal storage apart from the System. Once the process is complete, shut down the Mac, and its next user will receive it as if it had just been unboxed, factory fresh, with its current version of macOS pre–installed, ready for them to personalize and set up.
Some users also rely on this to completely “cleanse” a Mac which has been used in a high–risk environment, where it may have had malware or spyware installed, or even as a thorough annual housekeeping procedure.