The Receipt records are automatically generated when payment is received through any process that allows for payment. This should also automatically trigger a receipt email to be sent to the customer. However, you may run into a situation where you need to manually send the receipt email or resend it.
Navigate to the Receipt Record
This can be done from the regarding record or through advanced find, see both methods in the substeps below.
Navigate from Advanced Find
Look For Receipts
To narrow it down you can select Date Created
To narrow further you can look for Subject and/or Regarding
Click Results (if you selected regarding there should be only one record. If you select subject contains there may be multiple records)