I apologize, but the information I've found about your query doesn't include Clay's VAT number for invoice registration. Our sales tax information primarily covers how sales tax is calculated and collected for U.S. customers.To get the specific VAT number you're looking for, could you please contact our support team at support@clay.com? They should be able to provide you with the most up-to-date and accurate information regarding VAT numbers and invoice registration.
Source:How is sales tax calculated? - FAQ | Clay.com
Hey Federico, thanks for reaching out! We don't currently have registration outside the US, so there's no VAT for Clay.
The invoice does contain information that should generally be enough.