Hello @koupmi
It depends on how you modify the WooCommerce Checkout Page. If the Coupon Code field ID is the same as in the unmodified version of WooCommerce, the coupon should work.
I don’t know just how you are modifying WooCommerce. Are you adding the Coupon Code field to Checkout, with a plugin, or with code in the functions.php file?
Firstly, the ID of the Coupon Code field should be id=”coupon_code”. The WooCommere coupon mechanism our plugin is based on reacts to this ID and then the coupon value should be taken off the order.
If you have any further questions, let me know.
Best regards,