What are the heads up Texas Hold'em rules?

In Texas Hold'em, each player is dealt two cards face down, called hole cards. Five community cards are dealt face up in the middle of the table. Players use a combination of their hole cards and the community cards to make the best five-card hand. The player with the best hand wins the pot. Betting rounds occur before and after the community cards are dealt. Players can check, bet, raise, or fold during these rounds. The player to the left of the dealer button starts the betting action. The game continues until all but one player has folded or until a showdown occurs.