Adding a blank invoice In the Module menu, click Financial. In the Menu bar, click Invoices. In the Submenu, click Customer Invoice. Note: Clicking Invoices automatically directs you to the Customer Invoice submenu. Click Add. Select a Customer from the drop-down list. Select a Creation Date using the calendar button. Click Create. The invoice appears in the overview. Next, you can edit and complete the invoice. You will need to add revenue lines to the invoice.