There were many significant Law changes for 2019-2020. Referees are required to implement all of these changes, as adapted to each individual league, as of Fall 2019.
Free Kicks in the Box
Any free kick, including a goal kick, given to a team from within their own penalty area is in play when it is kicked and moves. The requirement that the ball leaves the penalty area is removed. Once in play any one from either team, except the original kicker, may play the ball.
Players from the opposing team are still required to remove themselves from the penalty area and may not reenter until the ball is in play. The kicking team may ask for enforcement of this requirement, a ceremonial restart. However, the kicking team may forego this requirement and decide to "quick kick", even with opponents still within the penalty area. They do this at their own risk and must live with the possible consequences.
The ball does not have to leave the penalty area to be in play from a goal kick before it may be played by either team. Double touch by the original kicker, even if the ball moves only slightly, would result in an Indirect Free Kick.
Setting a Wall
A completely new requirement involves "the wall" from free kicks taken outside a team’s penalty area. First, a wall is now defined as two or more opponents forming in a connected array, usually shoulder to shoulder. Second, if a "wall" includes three or more opponents the players on the kicking team are not allowed to be in it, on either end, nor within one full yard on either side of any part of this wall. Punishment will be failure to respect the required distance for a restart, card and Indirect Free Kick.
Goal Keeper Movement on Penalty Kicks
A goalkeeper defending against a penalty kick will be allowed to have one foot on any part of the goal line with the other on the field of play, prior to the ball being played. The goalkeeper may still move laterally between the posts before the kick as long as at least one foot remains on the goal line until the shot is taken. The goal keeper cannot move forward until a shot is taken. The goal keeper cannot stand behind the goal line nor lean against either goal frame or the net. The referee will initiate the kick with a whistle and the kicked will immediately kick the ball.