This feature is only available to the "Owner" of the account or an assigned treasurer/accountant. Once logged in as the Owner/Accountant, you are able to print your organization's monthly receipts. You can give this access to your treasurer by following the steps in this article on Giving Your Treasurer Access to the Billing Profile.
Steps for printing a statement:
First, click on "My Profile" in the top right corner. Select "Account Settings" from the menu.
Next, choose the "Billing and Payment Settings" tab and choose the invoice you would like to print.