For ex. we have

/www/configuration.php

(Or /www/joomla etc/configuration.php)

Now we would like move config content to /configruation.php (out of WWW directory).

1- Create a NEW.cf in / You will have /NEW.cf

2- Copy your  configuration content in /www/configuration.php to /NEW.cf

3- Change configuration content in /www/configuration.php to

<?php
require( dirname( __FILE__ ) . ‘/../NEW.cf’ );
?>

For more security, you may chmode the configuration in /www/configuration.php to 644

Good luck!