Engaged Element is an Insights feature that allows you to understand how your end-users behave in the underlying web application, even if you prefer not to use DXA due to security concerns.
Learn how to utilize Custom Events in Insights.
Learn how you can easily track any meaningful event on your website or application with Tracked Events.
Once you are familiar with Tracked Events, this article explains how to create a general Tracked Event.
This article explains the best practices for Tracked Events.