The three best places I would recommend for new Superman readers are the New 52, Rebirth, and a self-contained story. In 2011 DC restarted all of their books almost from scratch. Some events from before then still happened in this new timeline, but we only know which from whats referenced in the comics. Since then, DC Rebirth has set the world back closer to where it was before New 52, but that was very recently. If you are interested in a full, modern Superman run, New 52 is a great place to start. If you would prefer to get up to date quickly, skip ahead to Rebirth, and If you want to start with a great self-contained story, there are some great ones to choose from.
All the Superman lines have crossovers at some point, but you can pick a series and read it and the crossovers it takes part in without getting lost. I recommend starting with the first book of Action Comics, which retells Superman's origins, and then read Superman and the crossovers it's a part of:
Rebirth is a great place to start, except that there's not a lot published yet. There are two main series, Superman and Action Comics, but last year's series "Superman: Lois and Clark" introduces the Superman currently being depicted in Rebirth:
DC has a strong culture of totally independent books, where writers can tell the stories they want to tell, without needing to make it fit in with a big established universe. Below are six of the best totally independent Superman reads: