What is the function of the commutator in a dc motor? to spin the magnet to change direct current into alternating current to change alternating current into direct current to spin the wire coil

Commutator is an attachment, connected to the armature of motor or generator through which electrical connection is made and ensures that the current is flowing like a direct current
And it is a device for reversing the direction of flow of electrical current.
In addition by using induction the current is induced in a circuit due to a change or motion in a magnetic field is so directed as to oppose the change in flux "is the surface magnetic divided by time" and to exert a mechanical force opposing the motion of the spin of wire coil.