This plugin records each coupon code used for an order in an order meta field for reporting purposes. The data recorded reflects coupons added to the order and persists even if the order’s coupons are later modified or deleted.

To report on the fields created by this plugin, check out Product Sales Report Pro (for reporting on product sales totals filtered by coupon code used) or Export Order Items Pro (for exporting individual order items with the order coupon code as a column – use only for orders that have no more than one coupon code).

Order Coupon Field for WooCommerce