What is an identifier, and why should you specify it during the ordering process? An NPMLD XX XX XX XX identifier is a unique registration number that uniquely identifies your shipment. Make sure to enter these nine digits in the online store's order form. The seller, in turn, will note the identifier on the product label when sending it to our foreign warehouse for delivery. Thanks to this process, the shipment will not be lost. This number will help determine the recipient in case the order's tracking number was not registered in the personal account when the shipment arrived at the warehouse. Depending on the settings of the online store, the identifier may be specified in a different address or data field when completing the order form.