In the different variants of poker community cards that are used, as in the case of Texas Hold’em or Omaha, the 3 flop cards that are placed face up on the table is the second of the four rounds of a hand.
In this round are drawn to the center of the table the first three community cards, face up, and the action begins again starting with the small blind, the player to the left of the button.
The cards that make up the flop should always be removed from the top of the deck and, to avoid scams the first of the cards that was on top of the deck for the duration of the first round of betting is eliminated without teach and thus take the forming the flop (this is called “burning” the first card).
To see the flop you need more than one player remains in the hand after the first round of betting, because if the players leave the hand, the remained player wins the hand automatically, without the need of the first three common cards.
In the situation in which several players remain after the first round of betting (preflop), so that players can “see the flop”, it is mandatory that these have bet the same amount to the pot.