Exchange Customer Data
From the Payment Details screen, you'll also see a link there to View Customer Data. That link takes you to a link with 3 tabs:
The Products tab shows you and all products that customer has purchased along with the transaction number.
The Transactions tab shows you every transaction that client has had on your site and allows you to view the transaction, resend confirmation email or refund through the payment method used.
The last tab, Info, is where you can make notes about the client.