Headers & Volleys is a friendly game mode in FIFA and FUT where goals will only count from heading the ball or from a volley shot. Free kicks and penalties will also count in this mode.
How to Play Headers & Volleys Mode
Max Chemistry friendly mode is available in FUT 21 > PLAY tab > FRIENDLIES (Couch Play / Play Online / Play A Friend).
In FIFA Kick-off mode, it is available under House Rules mode.