Joomla provides the administrator with an extremely simple method of checking your system information. This option is available through System > System Information.
You can also create a very simple PHP script. Include the following codes in your PHP file and upload this file to your site. Try accessing this file on the browser, you'll see the same information is being displayed for you.
<?php
// This is a very simple method to load up php's settings.
echo phpinfo();
?>