Change ownership of old MacBook Air
I have been given a 2015 MacBook Air that has barely been used. It is badly organized and I don't have access to all the passwords. I have two questions:
1) Is there a reliable guide to making the necessary changes to the names of the computer, the users, and passwords?
2) Should I give up on this mission right now, before I waste a lot of time on it?
Many thanks, in advance.
MacBook Air 11″, macOS 10.13