Hello there. Displaying the company's VAT number on the invoice is a straightforward process you can achieve in just a few simple steps.

Let's get started by going to the Taxes menu. Then, proceed to the following instructions below:

1. In the upper right corner, select the Edit Tax dropdown button.
2. Choose the Edit settings option.
3. Enter your VAT number in the Business ID No. field.
4. Click on Save.
   
   

Once done, the system will automatically populate the VAT number on your invoices moving forward. See sample screenshot below:

To personalise and add specific info to your sales forms, check out this article: Customise invoices, estimates, and sales receipts in QuickBooks Online.

You're always welcome to send a reply or create a new thread if you have any other invoice-related concerns. I'm always prepared to provide appropriate information and resolutions. Take care.