Barcode numbers are typically divided into two parts: a company code prefix, which is assigned to the entire system, and the remainder of the code which designates a particular product within that system. Barcode Prefix Example illustrates a typical barcode with a prefix.

The system uses prefixes in barcode labels to identify a customer or ship‑to code, while the remainder of the barcode identifies additional information about the item or shipment. Warehouse staff scan barcode shipping labels when building shipments for the customer or ship-to code. The system needs to know the barcode prefix to validate that the correct barcode data value has been scanned.

See here.