It's a open sandbox where there are a lot of "careers" or playstyles you can pick from. The most popular one would be joining a player corporation (guild) and fight against other corps for territory. There are miners who mine astroids for resources and sell it for money. Others use said raw materials and set up factories to refine it into different products. You can be a space trucker and haul them, or you can even be a space pirate and attack and loot said truckers. Of course there are more traditional dungeon raid esque PvE with your corp.

The (in)famous thing about EVE is that it's a space spreadsheet simulator. (It's not completely unfounded as there's an official EVE Online add on for Excel, but unless you're doing space business you don't really need it. I never did). The learning curve is also pretty steep. But it's pretty fun, and the harshness of space does create some great space friends. As they always say, the best ship in EVE is Friendship.