This is the type of bend that is created by the addition of bends to a SolidWorks model that has sharp corners and a uniform thickness across its sections. Sharp bends, round bends, and flat bends are the three types of bends that may be applied when converting a solid body to a sheet metal part using the Insert Bends or Convert to Sheet Metal tools.
Knowing the basic bend types will assist you in understanding the different ways to bend a part in SolidWorks.