STEAM FAMILY IS A THING?

I am REALLY really new to modern PC gaming, and I just sold off my ps4 because the games cost a lot, I just made a budget PC and now someone told me steam families are a thing and people add other people?

I consider myself, sort of a story game veteran I have played Prince of Persia's series, completed half life (best game ever btw), used to be really good in CSGO when my core 2 duo PC could run it, finished the LOU series, finished horizon forbidden west, Assassin's screen origins. But rn I'm looking to play some souls games like elden ring, Bloodborne and other good story games so idk if anyone wants to share then I'll be more than happy to join.

I play the piano if anyone wants to check that out (@areeb_new_n_improved) Instagram.