Answer:
The Majority floorleader is chosen by the party that has the majority in each chamber of congress: there is a senate majority leader, and a house majority leader.
The minority floorleader is elected in the same manner, by the party that has the minority in each chamber of congress.
Both Majority and Minority leader have the main function of representing their parties position on issues. However, the majority leaders have much more power because they also represent their respective chamber (House or Senate), and they arrange the order in which bills are discussed.