I hadn’t realized these tricks, but as I use the thing more, I’m learning, but for MacOS, here are some good things to know
First is that you can actually add faces to the system. It is a little complicated, but in Mac Photos, what you do is to go to a Photo, and then get the Info
 dialog up, you will see a section called faces and a +
 icon, click on it and it will let you position a circle where you should put the face. While Photos is pretty good at finding faces, it does make mistakes and iMore has a great list of tips:
Changing photo names is easy if you turn on View Face Names
 in the main menu, then there will be a bubble with the name of the person, just type the real name and it is integrated with Apple Contacts, so you can tie it all together.
Memories is a bit of strange feature I don’t totally get yet, but it is trying to do intelligent events.