Football Associations play an integral part in the administration of football in their area of sovereignty. They are the guardians of the sport if we can put it in the simple words.
They are the apex legal bodies who make decisions on all the matters pertaining to football. Matters like to maintain law and order in the nation’s all footballing competitions, maintain discipline, and also to implement the the rules which are set by the apex governing body of football, i.e. FIFA.
The FA’s also take care of the brand which the football projects about their country and their footballing culture on the whole. They also voice their concerns to the higher authority regarding the state of the game in their country.
The hierarchy of these bodies is – national Body -> Continental Body -> FIFA.