Google Analytics is a WordPress plugin used to clearly understand important things like who uses your site and how, and what they do on it. It can be installed easily enough, is free, and has loads of valuable displays and graphs. It, as the name implies, is run by Google, so it prefers to be accessed via Google account, though it does allow other ways.
It can be installed through multiple options, such as Site Kit or Monster Insights. after installation, it opens a new bar in the WordPress Dashboard that lets you see all of the information it has. A few of the graphs can be confusing, but should all be possible to understand with just a little research.
Sources: https://www.wpbeginner.com/beginners-guide/how-to-install-google-analytics-in-wordpress/ and https://www.youtube.com/watch?v=njri8_gJTs0