Duty to prepare and produce triplicate manifests and obtain written permission before departing a customs station. Regulation 6 requires the person-in-charge to prepare triplicate manifests in the prescribed form for each customs station, deliver a manifest and the relevant bill(s) on arrival, obtain the proper officer's endorsement with one copy retained by the officer and two returned, retain one returned copy as the carrier's record and present the other at the loading station, and prohibits departure from the customs station until written permission is granted by the proper officer after checking the manifest.