1. Go to Communities > forms > single step donation 
  2. Hover over the form name 
  3. Click Website Info 
  4. Click Donation Form Options
  5. Select the Confirmation Text tab
  6. Click on the Advanced Confirmation Setup link.
  7. To enable Advanced Confirmations, select Use Advanced Confirmation Setup
  8. Click on the Edit link for the Donation Confirmation.
  9. Select Use Account Default Text or Customized Text
  10. Click on the Edit Email link to edit the email content, if you selected Customized Text
    • Make any appropriate changes and Save