Preventing X-XSS-Protection header missing, X-Content-Type-Options etc

How can issues such as X-XSS-Protection header missing, X-Content-Type-Options missing etc be prevented in Codeigniter ?

I have used the following code in header.php :

Code:

<?php
header('X-XSS-Protection: 1; mode=block');
header('X-Frame-Options: deny');
header('X-Content-Type-Options: nosniff');
header("Content-Security-Policy: default-src 'self'; script-src 'self' 'unsafe-inline';");
?>