FMCSA operating authority is often identified as an "MC," "FF," or "MX" number, depending on the type of authority that is granted. 10 steps to getting your California trucking permits.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. Apply for your trucking authority. It's the letter from FMCSA with the date your authority went active and what authority was granted. Applying for trucking authority gives your company permission from the US government to receive payment for hauling freight as an independent company. Speakers will be required to complete and submit a speaker request form to Clerk staff. An Operating Authority Letter includes a company's name, address, USDOT Number, and MC number. This letter is necessary for booking loads.