Within Teamwork Projects you can view your monthly or annual invoices from the site settings.

Note: Only a site owner or site admin can access the site settings.

To view, click your profile image in the top right corner of your site, and select 'Subscription' from the dropdown:

In the Subscription area, you will see a list of any past invoices associated with the account below your plan summary:

Note: If you choose to pay via PayPal you will not receive an invoice to view in this area. Invoices for payments through PayPal can be viewed with them directly.