What does the flagellum do?

well the flagellum move by basically swinging its whip like tail

flagella are projections from the cell. They are made up of micro tubules . They are motile and designed either to move the cell itself or to move substances over or around the cell. The primary purpose of cilia in mammalian cells is to move fluid, mucous, or cells over their surface. Cilia and flagella have the same internal structure. The major difference is in their length.