The force that causes most of the plate movement is thermal convection, where heat from the Earth's interior causes currents of hot rising magma and cooler sinking magma to flow, moving the plates of the crust along with them.
Answer: Its simple your answer is below and i got this information from study.com and im not saying you should report me for going to it or nothing but this answer below is 100% correct and not plagiarized
The force that causes most of the plate movement is thermal convection, where heat from the Earth's interior causes currents of hot rising magma and cooler sinking magma to flow, moving the plates of the crust together with them.