add_filter('woocommerce_order_item_display_meta_key', function($display_key) {
    global $WCFM, $WCFMu;

    if ($display_key == 'wcfm_tracking_code') {
        $display_key = __('Tracking Code', 'wc-frontend-manager-ultimate');
    }

    if ($display_key == 'wcfm_tracking_url') {
        $display_key = __('Tracking URL', 'wc-frontend-manager-ultimate');
    }

    if ($display_key == 'wcfm_mark_as_recived') {
        $display_key = __('Item(s) Received', 'wc-frontend-manager-ultimate');
    }

    return $display_key;
});