In order to track the results of your store in Google analytics, you need to generate the code following Google instructions.
After you follow the steps from their tutorial, you will get a code that looks like the following:
var _gaq = _gaq || ;
ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
var s = document.getElementsByTagName('script'); s.parentNode.insertBefore(ga, s);
UA-AAAAA-A is a unique code that was given to your store by Google.
After you generated the code (UA-AAAAA-A), you need to add it on your website. In order to do so, follow a few simple steps.
Log in to your admin panel and navigate directly to Stores => Configuration
Then under Sales, find Google API.
Now click to expand Googla Analytics section, select “Yes” to enable and enter the code (UA-AAAAA-A). Don’t forget to press “Save Config”.