In Omaha poker, each player is dealt 4 hole cards, which is twice the number of hole cards in Texas Hold'em. Therefore, the number of possible 5-card combinations using the hole cards and community cards is several times greater than in Texas Hold'em.
The first thing players need to understand is that the number of starting hand combinations is not twice, but six times that of two-card combinations! As such, the probability of forming the best possible hand is slightly higher than in Texas Hold'em. With more variables at play, this is one of the features that attracts players to Omaha poker.