Players catching the ball in the end zone must get two feet down in bounds in order to score a touchdown. The key stipulations are that the player also possesses the ball and the ball crosses the goal line. If a player has his feet in the end zone but receives the ball short of the goal line, this is not a touchdown by NFL rule. A catch made in the end zone requires two feet down and control of the ball on or past the goal line to be a touchdown.
Previously, an NFL receiver leaping to make a catch in the end zone did not have to get any feet down. If he was forced out of bounds by defenders and the referees determined that he would have come down in bounds, his team would be awarded a touchdown anyway. This rule was changed by the NFL. Now on those plays, a receiver must get two feet down regardless.
However, there are still ways to score a touchdown without setting foot in the end zone. A ball carrier needs only to stretch the ball across the goal line to score a touchdown. His feet need only to be in bounds.
NFL touchdown rules differ from those of college and other professional leagues. In college, a receiver is required to get only one foot down in the end zone to score a touchdown. The Canadian Football League also plays according to the one-foot rule. At 60 feet deep, the CFL end zone is larger than the NFL's 30-foot-deep,160-foot-wide end zone. NFL touchdown rules are still met with some controversy, but the league has been quick to rectify any gray areas to avoid conflict. With the abolition of the force-out rule, most touchdown rules in regard to foot position are cut-and-dried.