Date order on email

Hello i’m customize email template and i need to add the date of order on email (all email).

I put this code but when i recive email i not see any date. Why? Where wrong?

<strong style="font-size: 16px;">Riepilogo Ordine</strong><br />
<strong>Ordine n. </strong><?php echo $order->id; ?><br />
<strong>Data </strong><?php echo $order->get_order_data; ?><br />
<strong>Metodo di Pagamento </strong><?php echo $order->payment_method_title; ?><br />
<strong>Dettagli di Pagamento </strong><?php echo $order->payment_method_description; ?>

This same happen with payment method. I like to see istruction but i see nothing ??

Thanks