The use of layers is a simple concept of organizing drawn and reference information. You will experience layers in most if not all digital creative programs.
Layers in CAD relate to the practice of overlaying drawings to provide increased levels of information, they provide you with the ability to switch and display the information, as you require it. With layers a drawing may not always be what it seems, it will often have many layers of additional information that you can access by turning the layers on and off. The ability to compose different types of information into different drawings, from one drawing file, is a very powerful organizational and data asset.
Layer organization: types and uses
2D and 3D layers You can ...