The three components you need to vape are; a tank, a battery and e-liquid.

The Tank
There are three main types of tank; The regular tank (which can be either an MTL or a Sub Ohm), an RTA and an RDA.

E-Liquid
There are three or four parts to e-liquid; propylene glycol, vegetable glycerin, flavouring and in some cases, nicotine. The liquid is poured into the tank and heated. When the liquid evaporates, it creates a water based vapour. This action is called vaping.