The main difference between a single-elimination bracket and a double-elimination bracket is that in a double-elimination bracket, the team that lost is not eliminated from the tournament. Instead, they move to compete in a separate "losers" bracket. In the end, the winner of the "losers" bracket competes against the winner of the main bracket.
Double elimination brackets have winners and losers brackets. A team that won a match is placed in the winner's bracket, whereas a team that has lost the match is placed in the loser's bracket.
A double-elimination bracket is a popular tournament format since it allows teams to continue competing even after losing. Aside from adding an element of strategy, teams must decide whether to take chances and win their matches in the winner's bracket or to play it safe and return from the loser's bracket.