Depends how the 2D drawing looks like. When the object is i.e. a closed polyline you can extrude or revolve it, or you can use sweep or loft by using a path and in the case of loft, using more 'profiles'. So in 2D you draw your Profiles from where you want to make a 3D solid or 3D mesh. Additionally you can draw 2D paths to 'guide' the extrusion. Those paths may not lie in the same UCS-plane.