Navigation drawer lets the user quickly access top important sections of the interface, and represents a part of multi-level navigation. It suits apps and web-services with five or more significant destinations, which are often unrelated.
This element is built on three principles:
Clearness and list-like look: explicit laconic naming of sections in the form of the list
The inner hierarchy of the list reflects the significance of the section: higher importance takes a higher position
Contextual nature: it can be shown or hidden by pressing the icon.