How are tectonic plates able to move?
Tectonic plates are moved by convection currents underneath the crust in the mantle.
These convection current is created by molten rock rising, giving off heat and falling back down. This process creates a large swirling current which in turn moves the plates around making them bump around and move (causing earthquakes).
Fun fact, the tectonic plates move 2.5cm per year!
Image reference: windows2universe.org