title: Save custom values from Woocommerce checkout as custom order meta data
body: <p>In Woocommerce, I have a checkout page (review order) with custom data.
  I need to find a hook to register some custom data (<code>$totaleiva_1</code> and <code>$totalefinitocarrello</code>) in the order and then I have to send them in email new order.</p>
  
  <p>I'm not able to make it for instance. Any advice or help please?  </p>
  
  <hr>
  
  <p>Edit - That is my code:</p>
  
  <pre><code>$totaleiva_1 = 0; 
  $items = $woocommerce-&gt;cart-&gt;get_cart(); 
  foreach($items as $item ) { 
      $totaleiva_1 += $totalForSebeneArray[$item ['data']-&gt;get_id()]; 
  } 
  $totaleiva_1 = number_format($totaleiva_1, 2, '.', ''); 
  $totalefinitocarrello = $totaleiva_1 + $total; echo "&amp;euro;"; 
  echo $totalefinitocarrello; 
  </code></pre>