All Mountains are built through a general process called "deformation" of the crust of the Earth. Deformation is a fancy word which could also mean "folding". An example of this kind of folding comes from the process described below.
When two sections of the Earth's lithosphere collide, rather than being subducted, where one slab of lithosphere is forced down to deeper regions of the Earth, the slabs pile into each other, causing one or both slabs can fold up like an accordion. This process elevates the crust, folds and deforms it heavily, and produces a mountain range. Mountain building and mantle subduction usually go together.
