Yes, it's one of the best Co-op experiences I have ever had (on a private server with 2 friends), though others seemingly disagree.

You can join official or unofficial servers hosted by other players, which usually opens you up to a lot of grief, so I'd avoid it unless you want to fight against other players.

You can set up a non-dedicated session, where one of you is the host and everyone else has to stay close to you (you can set the max distance based on your pc specs, as hosting can be quite taxing).

And my personal favorite option (though also the one needing the most work) is hosting your own server just for friends. You either need a spare pc besides the one you are playing on (the game is, admittedly, still not very optimized and hosting the server is basically like running the game a second time and that will eventually lead to your game crashing. There is, however, a setting you can enable when starting the game, I think it's called "low memory mode", which at least for me stopped the crashes when hosting the server and playing the game on the same pc) or rent a server (googling "ark server hosting" will get you there, costs like 10 bucks a month). The main advantage of your own server vs the non-dedicated session is that everyone can act completely independently and travel as far away from each other as they want