It is worth to mention that WordPress doesn’t have Google Analytics support out-of-the-box. To add the Google Analytics code for your WordPress website you need to relay either on the WordPress theme or plugin.
Once you installed the plugin, please navigate to the Settings section in the WordPress dashboard.
From the Settings section select Google Analytics Setup and add your tracking code. From now on, on all your website pages you will have the tracking code enabled.
Also check GA Analytics on Github. NOTE: It requires at least WordPress 4.5.
Here is the link to Google Analytics.