How to factory reset a Mac: Quickly erase everything

If you're planning to sell or give away your Mac or want to start fresh, you may want to do a factory reset. This can be done by using the "Erase All Content and Settings" feature, which quickly erases all the settings, data, and apps on your Mac. In this guide, we walk through the steps required to factory reset your Mac using Erase All Content and Settings.

Source : https://www.pocket-lint.com/how-to-reset-mac/