Aluminum that has been folded or creased into shape such as being thin would be sheet aluminum but if it's tubular or something such as Aluminum Window Frames, Aluminum Door frames, patio chairs aluminum heat sinks etc then that would be extruded.
Extruded Aluminum gets it's name because of the process that was used to make the aluminum as it's pushed through a die to form it.
For your scrap yard to accept the aluminum though as clean you need to make sure there's no screws or caulking etc or any other metal other than aluminum on the scrap aluminum you plan to sell otherwise it will just be dirty unclean aluminum.