What is the 7 point tiebreaker rule in tennis and how is it implemented during a match?

In tennis, the 7-point tiebreaker rule is used when a set reaches a 6-6 tie. Players then play a tiebreaker game to 7 points, with a lead of at least 2 points needed to win. The tiebreaker is implemented by players taking turns serving every 2 points, starting with the player who did not serve the last game.