Google Analytics is a system designed by Google that tracks metrics or statistics of a particular website. By adding Google Analytics to your website, you can track the amount of visitors to your website, the keywords they used to find your website, the names of search engines or other websites that referred visitors to your website and more.

Google analytics in your website will help you to analysis the proper report of the site

How to use google analytics in website ?
 

Add Analytics tracking
On a computer, open a classic Google Sites.
Click Settings. Manage site.
Under "Statistics," click the Down arrow. Use Universal Analytics.
In the text box, under "Analytics Web Property ID," enter a valid Analytics Property ID. ...
At the top, click Save.

first set up a Google Analytics account and then add tracking code to your website.