要添加其他订单注释自定义字段，请执行以下操作：

外接程序功能。php：

/**
 * add new order note field
 */
add_filter( \'woocommerce_checkout_fields\' , \'customizing_checkout_fields\', 10, 1 );
function customizing_checkout_fields( $fields ) {

    // Define new  custom Order Notes field data array
    $customer_note  = array(
        \'type\' => \'textarea\',
        \'class\' => array(\'form-row-wide\', \'notes\'),
        \'label\' => __(\'Order Notes New\', \'woocommerce\'),
        \'placeholder\' => _x(\'Notes about your order, e.g. special notes for delivery.\', \'placeholder\', \'woocommerce\')
    );

    $fields[\'order\'][\'billing_new_customer_note\'] = $customer_note;

    return $fields;
}

/**
 * Process the checkout
 */
add_action(\'woocommerce_checkout_process\', \'customise_checkout_field_process\');
function customise_checkout_field_process()
{
  #if the field is set, if not then show an error message.
  if (!$_POST[\'billing_new_customer_note\']) wc_add_notice(__(\'Please enter Order Notes New value.\') , \'error\');
}

/**
 * Update the order meta with field value
 */
add_action(\'woocommerce_checkout_update_order_meta\', \'custome_checkout_field_update_order_meta\');
function custome_checkout_field_update_order_meta($order_id)
{
  if (!empty($_POST[\'billing_new_customer_note\'])) {
    update_post_meta($order_id, \'billing_new_customer_note\', sanitize_text_field($_POST[\'billing_new_customer_note\']));
  }
}

Display field value on the order edit page

add_action( \'woocommerce_admin_order_data_after_shipping_address\', \'custom_checkout_field_display_admin_order_edit\', 10, 1 );
  function custom_checkout_field_display_admin_order_edit($order){
        echo \'<p><strong>\'.__(\'Order Notes New\').\':</strong> <br/>\' . get_post_meta( $order->get_id(), \'billing_new_customer_note\', true ) . \'</p>\';
    }

Display field In Order review page after order note

add_action(\'woocommerce_order_details_after_order_table\',\'custom_checkout_field_display_order_reviews\',20);
    function custom_checkout_field_display_order_reviews( $order ){  
        ?>
        <table class="woocommerce-table shop_table">
            <tbody>
                <tr>
                    <th>Custom order note </th>
                    <td><?php echo "<strong>".get_post_meta( $order->get_id(), \'billing_new_customer_note\', true )."</strong>"; ?></td>
                </tr>
             </tbody>
        </table>
    <?php }