A corner kick is awarded to restart the game from where the ball just went past, and was declared out of bounds by the referee.
In simple words, this is a way of restarting the game. Each corner is positioned at corner positions.
It’s the place from where a free kick or shot is taken by an attacking team against a defending team, in case the ball has gone out of play over their goal line after being last touched by one of defending team’s players.