3. Serial number and tracking number
There will be a serial number or tracking number on the package manifest. For surface mail without tracking, use a serial number, while for those with tracking, use a tracking number. This number can assist courier companies and customers in tracking and querying packages to ensure that they can be safely delivered to their destination.
4. Bag number
The postal bag number refers to the corresponding number of the large bag containing the package. In cross-border logistics, due to the large number of packages involved in transportation, it is necessary to number these bags for tracking information.