When is reverse charge applied?
billwerk will automatically apply reverse charge, if four preconditions are fulfilled:
A valid VAT ID has to be saved at "Settings > Account > Company".
The customer saved a valid VAT ID in his customer details. (The validity check is described here)
The customers company is not in the same country as your company, but it's inside the European Union.
The customers company must be located in a country for which you have allowed reverse charge in the tax policies.
If all of them is correct, billwerk will automatically use reverse charge and will display this on the invoice with a specific text.
If the country of the VAT ID number differs from the country of the invoice address, the country of the VAT ID number is used for invoice generation and taxation.