Open cart 2.+
1. In the admin panel of your site, open the "Modules / Extensions" section.
2. Select "Analytics" in the filters.
3. In front of Google Analytics , click the "edit" button if Google Analytics has not been installed yet, then click "+" to install.
4. Next, you need to paste the code into the Google Analytics Code field and set the status to be enabled. Then save the changes.