How do I add my company VAT number to my invoice template?

Hello Kate25, 

Welcome to the Community page, 

If you got to the taxes tab on left hand side> edit VAT>edit setting> in there you put your VAT number in and then it will post it on the invoice for you and you'll be able to see this when you go to print or preview the invoice, it will show on the top left hand corner of the invoice print or preview page.