The Invoice Info page can be accessed by going to the "Options" button from your main dashboard page. Click on "Account Settings":
And then by clicking on "Invoice Info":
Once on the page you will have the following options:
Invoice Logo - This will show on the top right of your invoices. Click the image to choose an image from your computer. If you want to replace the image simply click it again and choose another image.
Invoice Footer - This is a general text entry box for you to put any other required information you want to show on all invoices.
Billing Address - This is the address that will show on the "TO" portion of the invoice. As in Project.co all payments are made from others to you as the account owner.