Redirect and Reload

Before outputting page content

Note this must be before any html headers are sent (i.e. in php code before html output)

Redirect to a new page
	header("Location: index.php");
	die();
Reload the current page 
	header('Location: '.$_SERVER['PHP_SELF']);
	die;

The php header function

Redirect with check you’re not already on target page
  if (strpos($_SERVER["REQUEST_URI"], 'home-holding') === False)
  {
    wp_redirect( home_url( '/home-holding') );
    die;
  }

If you’ve outputted some page content

JavaScript method
  $HtmlOutput .= <<<_END
    <script>
      window.location = "https://somedomain.com";
    </script>";
_END;
Using META tag method
<META HTTP-EQUIV="refresh" content="0;URL=index.php">