To hide applied coupon from the cart and checkout pages

functions.php

<?php // do not copy this line
add_action('wp_footer', 'wt_sc_remove_coupon_code_from_cart_checkout_totals_table');
function wt_sc_remove_coupon_code_from_cart_checkout_totals_table()
{
	if(is_cart() || is_checkout())
	{
		if( class_exists( 'WooCommerce' ))
		{
			?>
				<style>
					.cart_totals  .shop_table .cart-discount{ display: none; }
					#order_review  .shop_table .cart-discount{ display: none; }
				</style>

			<?php
		}
	}
}