The coupon report will let you see how many times a particular discount code was used in orders and the amount of total discount given for each as well.  

Note: This report can be accessed through Reports >> report type. 

First, select the report type to find specific details of the report and the example screenshot is above. Once selected click the filter to load the report. 

Well, now the tenth view type coupons report 

The coupon report displays the following information:

Coupon Name: Lists the name of the coupon.

Code: The code number that was used to activate the coupon on the front of the store.

Orders: Showing the number of orders used for this particular coupon.

Total: Total amount of all coupons used. The number is a negative number because the customer will receive a discounted price on a product or order using the coupon.

Note: If you want to create a coupon, go to Marketing > Coupon > create new

If you would like to look up a particular coupon, you can use "Filter" as a shortcut to search for it. Coupon can be filtered by selecting a start and end date  

Clicking the "Edit" pencil button will direct you to that specific coupon edit form under Marketing > Coupon