Fossil Fuels are formed naturally deep underground from the remains of dead plants and animals that are decomposed under extreme pressure for millions of years.  The fossil fuels are them extracted from deep in the earth's crust and burned as fuel to produce heat and energy.  The three main types of fossil fuels are Coal, Crude Oil, and Natural Gas.  The processes for extracting the fossil fuels from the ground include digging, drilling, and hydrostatic fracturing, or fracking as it is more commonly called.