Question

why do The crust plate move

Answer 1

due to conventional current of Magma Under The crust

Answer 2

Hi friend here is your answer

Three of the forces that have been proposed as the main drivers of tectonic plate movement are:

mantle convection currents— warm mantle currents drive and carry plates of lithosphere along a like a conveyor belt;

ridge push (buoyant upwelling mantle at mid-ocean ridges) — newly-formed plates at oceanic ridges are warm, and so have a higher elevation at the oceanic ridge than the colder, more dense plate material further away; gravity causes the higher plate at the ridge to push away the lithosphere that lies further from the ridge;

slab pull — older, colder plates sink at subduction zones, because as they cool, they become more dense than the underlying mantle. The cooler sinking plate pulls the rest of the warmer plate along behind it.