Action and reaction are always equal and opposite . Then how does a body moves ?!!?!?

Formally stated, Newton's third law is: For every action, there is an equal and opposite reaction. The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object.

You are talking about the 3rd law of motion. Here, Newton states that the action & reaction forces are equal & opposite . But, they act on 2 different bodies (object) & aren't balanced, so the cancelling out of the forces won't take place & an object will move.

Hope it helps ⚜