Magento has two possible tax/VAT number fields. The first is ‘Tax number/VAT ID number, code: taxvat’, which is assigned to the customer entity. The field name is somewhat confusing, as this is a field for personal (not business) tax numbers.
With Magento 1.7 and the core VAT number check, the ‘vat_id’ field was introduced, which is assigned to the customer address entity in order to store the check data together with the address. Since VAT calculation is usually based on the shipping address, only this field should be used for European VAT ID numbers of business customers.
Our extensions only use the ‘vat_id’ field to check numbers.
To activate the field, navigate to ‘Stores -> Configuration -> Customer Configuration’ and, within the ‘Create New Account Options’ section, set the ‘Show VAT Number on Frontend’ setting to ‘Yes’:
We recommend disabling the account-related field ‘Tax/VAT, code: taxvat’ to avoid misunderstandings on the part of customers. To disable the field, navigate to the ‘Customer Configuration’ settings and set the ‘Show Tax/VAT Number’ setting to “No” under ‘Name And Address Options’.
