Once registered for the service, you will be given an UK import VAT on parcels reference.
The parcels reference should be included on the outside of the parcel if you send parcels via a universal postal service provider, for example Deutsche Post or La Poste. For other parcel operators the reference should be included in documentation accompanying any parcels sent to UK buyers, for example the airway bill, from 29 March 2019.
The parcels reference enables parcel operators to identify that the seller has registered for the service to pay UK import VAT due and they can then deliver the seller’s parcels without any delays.
HMRC will receive data about parcels that are entering the UK. Parcels without the correct parcels reference may be delayed.