It is not possible to edit the billing address on an existing invoice. You can change your billing address and it will be used for all future invoices.

How do I change the billing address on my invoice?

1. Log in to the Customer Control Panel

2. Click on 'Customer details' on the control panel on the left

3. In the ‘Invoice address’ text box, enter your company name and the full address, including all details you want to appear on your invoices. 

4. Once you've made your changes, click the 'save changes' button.