The most common method. Select a "Neutral Plane" (the fixed face) and then select the faces you want to taper.
When creating a "Solid Boss/Extrude," you can enable the Draft icon directly in the PropertyManager to add an angle while the solid is being created. 7382zip
Below are the most likely ways to "draft a solid feature" depending on which software you are using. 1. In 3D Modeling (SOLIDWORKS / CAD) The most common method
If you are designing a physical part, "drafting" refers to adding a slight taper (angle) to vertical faces so the part can be removed from a mold easily. 7382zip