You submit a customs declaration at Customs to notify them of the goods that you are transporting. Before you can submit a customs declaration, you need an EORI number. This is an identification number that your company has to request from Customs once so that you are known there. After you have submitted a customs declaration, you will receive a unique number from them (e.g. Movement Reference Number (MRN)) for the submitted shipment.
You need this document number issued by Customs to pre-notify the customs documents at the terminal via Portbase. In Portbase, you link the customs data (MRN) to the required logistics data (which truck/container/trailer, terminal, times etc.). Through your pre-notification via Portbase, you ensure that all the required customs formalities are automatically arranged at the terminal. This way, your transport can be performed without delay.