I frequently face two pawn structures as black. I wonder which one is better:

I don't realy know and I guess it would depend on the position of the other pieces (especially rooks) and what not but I'm going to take a stab anyways lol

In the 1st one there is 1 open file and in the 2nd there is 1 semi open file for each color so hmm...

I notice in the first that black's queenside pawns are more advanced and I notice white has that c3 pawn there so therefore maybe Black can go for a minority attack there. The thing is though that white has a nice possible knight outpost at d4.

Its kinda hard but I'm just guna go ahead with the 1st position though since that minority attack seems appealing and I think a possible d4 knight there may be able to be kept at bay

These are formations typical of the French Defense.  In the first, White has either played d4xc5, or reacted to Black's ...c5xd4 by recapturing with a piece.

Speaking strictly of the pawn formation, this should slightly favor Black.  He has a central majority, his half-open file (the c-file vs the d) is more useful, and his support point at c4 is more advanced than White's at d4.  He also has the possibility of a Minority Attack on the Queenside.  So why would White choose to play this way?

Because in chess few advantages are pure.  Where one side gains something, he generally must concede something else in return, and it is the relative value which matters.  In the early middlegame, White having a Knight established at d4 can be very useful, eyeing the leap d4-b5-d6 for an advanced strong square, and enabling the pawn attack f2-f4-f5, putting pressure on the Kingside.  His risk for these opportunities is the slightly worse structure in an ending - but he doesn't intend to get to an ending!

In the second position, White has recaptured "normally" on d4 with cxd4.  He has more space, but will need to capitalize on that quickly before the Rooks are exchanged on the c-file.   Black needs to hurry these exchanges if he can, and get the Queens off as well if possible, because his only pawn move to counter White's center is ...f6, which is the most weakening method.  The more "weight" on the board when he does this, the more risk he must endure.  Alternatively, Black can seek to counterattack the weakness at d4 with pieces, tying White down to its defense, which slows White's prospects on the Kingside.  In general, slightly favorable for White due to the greater space, but Black should be able to defend.

Alot of good stuff here that I've pondered about aswell. Things are a bit clearer now. Thanks for all the answers.