Apply coupon discount via GET method in URL even if cart is empty in WooCommerce

Question

I have a plugin that sends an advocates referral coupon code to e-mails that they enter. When the audience receives this email I\'d like to create a flow where they can clic

Answer 1

add_action('woocommerce_before_cart', 'discount');
function discount( ) {
    global $woocommerce;
    $code= $_GET["code"];
   if(!empty($code)){       
    if(WC()->session->set( 'applied_coupons', $code )){ 
    echo '
Applied coupon!
';
        }
    }
}