The wild card is a feature that is offered at some, but not all, of the video poker variants. The wild card is always the Joker or the Deuce. This wild card can be substituted for any other card from the deck in order to help players achieve a winning poker hand. In Deuces Wild, for example, the wild card is the 2, which is where name of the game comes from. Another game is Joker Wild, where the Joker is the wild card. Some games might have more than one wild card, such as Joker and Deuces Wild. In this game, the 2 and the Joker are wild cards.
Video poker is a very volatile game, about four times as much as blackjack. In any form of gambling, short-term results mostly depend on normal mathematical randomness (what some might call luck). However, in the long run, results mostly depend on skill. If you play a game with a return of 100.76% perfectly, that does not mean that you will have a 0.76% profit every time you play. The 100.76% is an EXPECTED return. Much in the same way, if you flip a coin ten million times, the expected number of tails will be five million, but it is unlikely you will hit five million on the nose. Actual results will vary significantly from expectations, but the more you play, the closer your actual return percentage will get to the expected return.