Only account owners can see Billing information.
Once logged in as the account owner, select 'Account' from the dropdown under the owner name.
From there, you'll see the plan type and cost under the Billing tab.
On the Transactions tab, you can see charges based on studies launched, panel credits purchased, growth license or plan licenses purchased, credit issued, etc.
The owner can download the receipts for individual transactions:
*Please note that receipts are available for transactions that used a credit card, not for Account Credits.