The position of players on the field determines their roles and assignments. Each of the 11 players on a team is assigned to a particular position on the pitch.
A team is shaped up of one goalkeeper and ten outfield players who fill various defensive, midfield, and attacking positions. The number of players in these positions depends on the team's formation.
There are about 15 player positions that can be assigned to outfield players. Player positions can be dynamically changed during a game when there is a change in team's formation and tactics.
A player's abilities and skills will decide which position they are able to play. Player numbers are usually assigned to each position. It is very common to start player numbers from the goalkeeper and go up to the forwards - Where the keeper is number 1, and the striker is 11.
List of Positions
Here is the list of the positions including their types in real-life and in FIFA game: