Wagering requirements are only applied to bonuses i.e. when you play games with bonus cash or free spins. If you play with your own non-bonus money, there are no wagering requirements.
Many bonuses set restrictions for the kind of games the player can play with bonus cash and how that play contributes to meeting wagering requirements. For example, a casino might decide that bonus cash can only be used on slot games or only on table games and so on. A casino may also determine that a whole wager on a slot game goes towards meeting wagering requirements while a wager on a poker game will only contribute 50%. As always, it is important to read the terms and conditions to learn more.