A kick-off is a way of starting or restarting play :
Before a kick-off at the start of the match or extra time
If the player taking the kick-off touches the ball again before it has touched another player :
A dropped ball is a method of restarting play whenIf, while the ball is still in play, the referee is required to stop play temporarily for any reason not mentioned elsewhere in the Laws of the Game, the match is restarted with a dropped ball.
The referee drops the ball at the place where it was located when play was stopped, unless play was stopped inside the goal area, in which case the referee drops the ball on the goal area line parallel to the goal line at the point nearest to where the ball was located when play was stopped.
Play restarts when the ball touches the ground
The ball is dropped again :