Since the AdEx platform uses a balance locked in your account for campaign payments, your financial department might need both invoices and statements. Here's the difference between the two:
Account Statements: These documents are issued monthly and show the remaining balance in your AdEx account after all the campaign spending for that month.
Invoices: These are issued per campaign and show the actual amount spent on each campaign.
You can find both invoices and statements under the Billing tab in the left-side menu of your AdEx account. Just click on the one you need and download it by clicking on the eye icon next to it.