Each half begins with a kickoff. Teams also kick off after scoring touchdowns and field goals. The ball is kicked using a kicking tee from the team’s own 30-yard line in the NFL or from the 35-yard line in college football. The other team’s kick returner tries to catch the ball and advance it as far as possible.
Where he is stopped is the point where the offense will begin its drive, or series of offensive plays.
If the kick returner catches the ball in his own end zone, he can either run with the ball, or elect for a touchback by kneeling in the end zone, in which case the receiving team then starts its offensive drive from its own 20-yard line. A touchback also occurs when the kick goes out of the end zone. Punts and turnovers in the end zone can also end in touchbacks.
After safeties, the team that gave up the 2 points puts the ball into play with a punt or placekick from its own 20-yard line.