The formation refers to the positioning of the team's players on the field. The composition of a team determines the squad's playing strategy by displaying each player's position.
The responsibilities of players are not defined by the system; however, a player's position in the formation determines whether he or she has a defensive or attacking function, as well as whether they should play to one side or centrally.
Formations are commonly described by three, four, or five numbers, which represent the number of players in each row of the formation, from the most defensive to the most attacking.
For example, the 3–5–2 system comprises three defenders, five midfielders, and two attackers. Because the goalkeeper's position is always fixed, he is not counted in a formation. Depending on the game strategy and tactics required by a team's coach, many formations can be applied to a match, and formations can be switched throughout a game.
The formation setting is chosen by the team's coach before and during the game, and players must adhere to it.