This section allows you to add your Google Analytics tracking code to your website. Once you have pasted the code in and clicked save, the tracking code is placed into the source code of your website.
You will require a Google Analytics account to do this. For more information on how to find your tracking code, please refer to the following article: https://support.google.com/analytics/answer/1032385?hl=en
Google Analytics is a free tool from Google which lets you to judge how your website is performing based on user data. For example, you can see how many users your site has had in a specific time period, what pages have been visited, how long users stayed on your site, how many pages have been viewed, and so on. This will allow you reveal potential improvement areas e.g. pricing adjustments, or marketing opportunities e.g. popular products.