Plate - A plate is a massive, irregularly shaped slab of solid rock, both continental and oceanic crust, and upper part of the mantle. They divide the earth into a series of sections. They are relatively cold and rigid, interlock with each other.
{Size & Thickness may vary}
Convection Currents - The core distributes heat due to radioactivity. This heat is not evenly distributed which leads to hotter and cooler areas.

Fold Mountains - Form due to the powerful compression of 2 tectonic plates [Usually continental], which squeezes the layers of rocks so that the upfolds form the ridges and the downfolds form the valleys.
Eg. Himalayas, Andes & Alps

Plates move towards each other [Collide]
Continental and Oceanic Plates -