Energy types (a.k.a auras) lay the foundation for Human Design and are what your entire chart is based off of. It essentially describes how your aura's energy works. Once you know what your energy type is, you can then use that information to develop your strategy, or the correct way to live your life. Your energy type will also show you your authority, or how you are supposed to be guided through your life and when/how you will know when you're living in and out of alignment.
There are five different energy types; Manifestor, Manifesting Generator, Generator, Projector, and Reflector. Each different type has a completely different aura. Therefore they each have different gifts that they offer, a unique set of traits, and each must navigate through life with a different strategy in order to live their life with ease.