I’m trying to copy the coupon form from the checkout page to the cart page.
In the checkout page is the coupon field displayed as a hidden element, that it’s shown after a click on a url.
I’ve managed to move field with,
add_action( 'woocommerce_before_cart_contents', 'woocommerce_checkout_coupon_form' );
Read more here: woocommerce coupon in cart page like the one in checkout