B2C :
Commercial invoice
With SKU
Website link of the goods purchase
B2B:
Authorization - direct representative / Power of Attorney (POA) – original. In case of company it must be signed by person(s) empowered to represent the company; (usually POA must be signed by the company Board)
valid EORI and VAT ID number must be printed on POA
any document as commercial invoice or additional description of the goods has to be in english (nature of goods, material of which it is produced, exact purpose etc. (each information that enables correct classification of the goods).