How to erase your MacBook and restore factory settings before selling it

[RV_]

As long as we are on Apple here is one for the MacBook folks

Excerpt:

"Selling an old MacBook is a great way to put some extra cash in your pocket, but first you must wipe every last bit and byte of your personal data.

Tempted by a new M1 MacBook? Our tests of the M1 machines show a significant increase in performance and battery life over their Intel-based predecessors. Plus, the M1 MacBook Air boasts a fanless design for blissfully silent operation. And you might be able to get some money by selling your old Mac to help defray the cost of a new M1 MacBook. But before you do, you'll need to migrate its data to your new Mac and wipe the old one clean. 

Whether you are giving your Mac to a friend or family member, recycling or donating it to an organization, you'll want to erase your personal information and files before parting with it. That's a security measure you don't want to skip: Your Mac's hard drive is bursting with sensitive information that you wouldn't want to be accessible, even if you trust your laptop's next owner. There's always a chance that some malware could snake its way in and uncover your personal details.

Here, I'll show you how to remove all traces of your data and return your old Mac to its default factory settings. This story updates periodically."

All of that and more in the link with lots of Mac reviews etc Here: Full MacBook article