Navigate to:
  1.  Analysis > Reports > View all
  2. Select the Credit Card Processing category
  3. Next to the Processed Transactions with Student Details or the Processed Credit Card Transactions, click Run 
  4. In the Report select the ability to show details
  5. Click Generate
This form doesn't say which form specifically is used, but it will show specific gateways if you have more than 1, and the amount that was charged. This can then be associated with a specific form as the forms would have different amounts due.