The 'Partner ID' is the VAT number of the customer of the goods in another EU Member State, to whom the goods are sent. This customer or consignee of the goods is also referred to as the partner operator, or in other words the taxable customer, who declares VAT on the intra-Community acquisition (ICV). Incidentally, this does not apply in the case of triangular trade/ ABC transactions. All businesses in EU Member States that are liable for VAT must, pursuant to European legislation, have a valid VAT number. In EU Member States a VAT number always starts with two letters, the alphabetical country code of an EU Member State. These letters should be filled in first. The total length of the VAT number differs per Member State. In the online data application IDEP+ the VAT number is automatically checked against the European VAT number register.