Minecraft wiki entry for team, associated text: team list [<team>]
Lists all teams, with their display names and the amount of entities in them. The optional <team> can be used to specify a particular team.
team add <team> [<displayName>]
Creates a team with the given name and optional display name. <displayName> defaults to <team> when unspecified.
team remove <team>
Deletes the specified team.
team empty <team>
Removes all members from the named team.
team join <team> [<members>]
Assigns the specified entities to the specified team. If no entities is specified, makes the executor join the team.
team leave <members>
Makes the specified entities leave their teams.
team modify <team> <option> <value>
Modifies the options of the specified team.