How to Verify Your Joomla 3 Websites using Google Analytics.
Google Analytics allows Webmaster the ability to track page performance in real time. Google analytics does require a Gmail access as well as Webmaster site verification.
Google Analytics will allow you to track page views, devices and geography....
Traffic Data is stored and can be accessed years back should you require however this is dependent on the date you verify your website.
A few Joomla Templates allow webmasters the ability to paste the analytical property ID however the *head* page can be accessed by Template Manager - Select Template - Edit Personal CSS - Index.php should you be required to paste the Google Analytics Tracking ID.