Since the heading ban is not part of the LOTG it's up to each competition authority to promulgate their rule and so the rule will vary. See the following examples.
The AYSO National Rule is: "An indirect free kick will be awarded to the opposing team if a player in the above stated divisions, deliberately touches the ball with his/her head during a match."
The US Youth Soccer Association rule is: "All Players age 10 years of age and under shall not head the ball directly from the air in any match or competition, nor shall these players practice heading the ball in any organized team setting."
NOTE: The above rule is mandatory for all US Youth Soccer conducted events, including Regional and National competitions for the National Championship Series, and National Presidents Cup series. This rule is also mandatory for the US Youth Soccer National League, US Youth Soccer Regional Leagues, and the US Youth Soccer Olympic Development Program. Although not mandatory for US Youth Soccer State Associations, State Associations are strongly encouraged to adopt this Rule for state and local play.
An interesting variation from the Alexandria (VA) Soccer Association, a member of the VYSA, draws a distinction between deliberate and inadvertent:
U5-U11 Age Groups: No heading in practice or games
- In games, whenever the ball strikes a player in the head, play is stopped.
- The proper restart depends upon whether the player deliberately played the ball with his or her head. (Referee decision at U9-U11)
- If deliberate, the proper restart is an indirect free kick to the opposing team.
- If this occurs within the goal area, the indirect free kick should be taken on the goal area line parallel to the goal line at the point nearest to where the infringement occurred.
- If the play by the head is deemed inadvertent, then the proper restart is a dropped ball.