To locate this information within your event admin, follow the below steps:
1. Click Manage on your Event
2. Select Discounts
3. Click the Discount Code Reporting tab
You will now see two boxes - the one on the left is displaying the discount codes used per ticket type, with the one on the right displaying how many times each code has been used in total across all ticket types:
For information on how to set up a Discount Code for your event, see our guide on this here.