Complete Trucking Authority Packages. Our complete authority packages are designed to give you every filing actually required to get you on the road.FMCSA operating authority is often identified as an "MC," "FF," or "MX" number, depending on the type of authority that is granted. When you have filed all of the paperwork necessary to operate a trucking company, the FMCSA will send you a letter of authority. At DOT Operating Authority we are happy to help with any filing assistance you may need! In this guide, we explore the ins and outs of obtaining MC numbers and trucking authority in ten simple steps! Apply for your trucking authority. A trucker must have a federal US Department of Transportation (DOT) Number. As part of the registration process, you must provide your Federal ID number. As part of the registration process, you must provide your Federal ID number if you are involved in transportation services as a motor carrier.