Google Analytics Tracking Codes are used to send traffic data to Google Analytics. It’s a small snippet of JavaScript that can easily be added to any website so that the website operator can use Google Analytics to understand trends in their traffic.
Websites can either add the tracking codes to the HTML of each page of their website, or they can add the Google Analytics tracking code to their tag manager, if they’re using one. In order to get hold of the unique tracking code for a website, a website owner must first create a property in the Google Analytics Account.