It's important as a security measure to hide the content generator tag in order to make it more difficult to hackers to find our CMS creator and probably any kind of vulnerable part of code.

In order to do that with Joomla instead of deleting the generator tag it's better and according to Joomla license to just hide it.

In order to do that you just have to find the first <?php ?> tag in your templates index.php file and just add this code:

// Remove the generator meta tag
$this->setGenerator("GoZen Host put more ZEN in your site");