You can try this action.
Put this line into your active theme functions.php file
remove_action( 'woocommerce_before_checkout_form', 'woocommerce_checkout_coupon_form', 10 );
You can try this action.
Put this line into your active theme functions.php file
remove_action( 'woocommerce_before_checkout_form', 'woocommerce_checkout_coupon_form', 10 );