What is a VAT number? Is it mandatory?

A Value Added Tax identification number (or VAT identification number) is an identifier used in many countries, including the countries of the European Union, for value added tax purposes. It is a unique number that identifies a taxable person (business) or non-taxable legal entity that is registered for VAT.

If you do not have a registered VAT business or if you are in a country where no VAT applies, then you can leave this field blank.