Billing details are a requirement in the system to settle a balance for an affiliate. An affiliate will not be included in a settlement if the billing details are not filled.
Setting a Requirement for Billing Details
You can make the affiliate billing details as a requirement in the affiliate registration. For more information, see the article Custom affiliate registration form.
Setting a requirement for VAT information
By default, VAT/Tax Nr. is an optional parameter. If you want to make it a mandatory one, navigate to Settings -> Taxes.
You can enable if VAT should be required from affiliates by toggling the switch.