Code-Snippets-Functions/Execute a function on a child site/WooCommerce/add-if-customer-is-guest-to-new-order-emails.txt

add_action( 'woocommerce_email_customer_details', 'add_guest_label_to_email', 5, 4 );
function add_guest_label_to_email( $order, $sent_to_admin, $plain_text, $email ) {   
    // Check if customer is a guest
    if ( ! $order->get_user_id() ) {
        $guest_label = '<p><strong>Guest</strong></p>';
        echo $guest_label;
    }
}