This depends on the type of team you wish to create:
FBLA teams: exactly 2 (1 captain + 1 player)
FCCLA teams: exactly 5 (1 captain + 4 players)
Varsity and JV teams: at least 4 (1 captain + at least 3 more players), but there is no maximum number of players. For in-person Varsity and JV competitions, teams are made up of 4 students and are allowed 1 alternate player.