In Germany we charge 16% VAT from all customers except for a few exceptions:
Your company is located in one of the European Union countries (not Germany), we may be able to write you an invoice without VAT. For that you need to provide your VAT ID for your country. Also you are responsible to pay your local VAT for our invoice in your country.
Clients with businesses outside the European Union can also provide a VAT ID, if they registered for one.
For the United Kingdom, we have to determinate whether VAT rules from EU still apply for October. If not, we may need to charge you 19% VAT.
MBS Xojo blog