How to add VAT number and address to invoices for tax purposes?

In order to add a VAT number and address to invoices for tax purposes, click on the username and select the billing option from the dropdown.

After you select the billing option, click on business details. 

Enter your address information, and VAT number in the business details field and click on the save all button. This information will be visible on the invoice.

To see the information in the invoice, go back to the billing section and click on the invoice date as highlighted in the photo below. 

This will generate a PDF version of the invoice and you will see the information inside it.