title: Display custom checkout field value in Woocommerce admin order edit pages
body: <p>I have the function in functions.php:</p>
  
  <pre><code>// Hook in
  add_filter( 'woocommerce_checkout_fields' , 'custom_override_checkout_fields' );
  
  // Our hooked in function - $fields is passed via the filter!
  function custom_override_checkout_fields( $fields ) {
       $fields['billing']['billing_infos'] = array(
          'type'      =&gt; 'textarea',
          'label'     =&gt; __('Podaj NIP', 'woocommerce'),
      'placeholder'   =&gt; _x('Tutaj możesz wpisać NIP', 'placeholder', 'woocommerce'),
      'required'  =&gt; false,
      'class'     =&gt; array('form-row-wide'),
      'clear'     =&gt; true
       );
  
       return $fields;
  }   
  </code></pre>
  
  <p>This code is adding custom field to billing form. It's working fine because I see it when I make an order like normal user. The problem is with data from this field in admin panel. I can't see it. Any help on this please?</p>