title: Display order item estimated delivery date if product has specific custom field in WooCommerce
body: <p>I'm adding programmatically a product custom field (the estimated delivery date) as custom cart item data if the product is ordered from backorder.</p>
  <p>I want to display that information also on order items so it will be displayed on orders and email notifications sent to customer.</p>
  <p>Here's what i tried so far :</p>
  <pre><code>add_filter( 'woocommerce_get_item_data', 'display_acf_on_cart_and_checkout', 10, 2 );
  function display_acf_on_cart_and_checkout( $cart_data, $cart_item ) {
      if ( ($cart_item['variation_id'] &gt; 0 &amp;&amp; $cart_item['data']-&gt;get_stock_quantity() &lt;= 0
      &amp;&amp; $cart_item['data']-&gt;get_meta('_ab_preorder_checkbox') === 'yes') || isset( $cart_item['is_preorder_field'] ) ) {
          if ( $estimated_delivery_date = $cart_item['data']-&gt;get_meta('_ab_preorder_estimated_date') ) {
              $custom_items[] = array( &quot;name&quot; =&gt; __(&quot;Date de livraison estimée (précommande) &quot;, &quot;woocommerce&quot;),  &quot;value&quot; =&gt; $estimated_delivery_date );
          }
      }
      return $custom_items;
  }
  </code></pre>
  <p>The message is showing on the cart and on the checkout page :</p>
  <p><a href="https://i.stack.imgur.com/Ush32.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ush32.png" alt="enter image description here" /></a></p>
  <p><a href="https://i.stack.imgur.com/ezfn4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ezfn4.png" alt="enter image description here" /></a></p>
  <p>But not on the invoice/emails sent to the client :</p>
  <p><a href="https://i.stack.imgur.com/ZSw9N.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZSw9N.png" alt="enter image description here" /></a></p>
  <p>I would like it to show up on like on the screenshot below <em>(in the red rectangle)</em>. Is it possible?</p>
  <p>Any help is appreciated.</p>