You need to go to the BATF site and make sure that the dealer your sending it to is in business . It doesn't have to go in the package. Write File copy on it if not already don should you decide to include it. Type a letter and address it to the FFL with youir name and information and the serial # description and the transferee of this gun put it in thebox along with the gun. Make sure you insure it and write the serial number down on the insurance receipt.Make sure the gun is disassembled ..bolt out of the rifle . SHotgun doesn't matter. The FFL from our dealer should be sent in a separate envelope with a letter and payment for the gun in question. For more information go to the BATF site

https://www.atfonline.gov/fflezcheck/