For tax purposes, we need to include our VAT ID in the monthly invoice.

You can update your billing details to include your VAT ID on the receipts. Users with the role of Billing or Owner can update this information by going to the Organization's Settings (left side bar) > Usage & Billing > Subscription > (Edit) Billing Information.

Note: You must have either Billing or Owner permissions to access and/or make changes to this information.

It is the responsibility of the org to enter the correct billing details in order to charge he appropiate taxes/VAT.

We are not able to edit past invoices as covered here: I need to edit/correct a previous invoice.