This PHP code enables you to programmatically remove the coupon code field once the first coupon code is entered & applied. Customers cannot enter another coupon as the coupon box is removed at the same time as the 1st coupon is applied as seen in the demo video.
Note : You can use the WooCommerce Marketing > Coupons > Coupon Data > Usage Restriction > Individual use only setting to do the same thing however this code enables you to integrate usage with WooCommerce extensions and other conditions using PHP.
There’s only 1 step :
Copy & paste the PHP code to the end of your child themes functions file or custom functionality plugin.