Raw events are events that haven’t had a label applied to them yet. They are generated using autocapture, which collects and stores every user action performed on each of your site pages. Their label is suggested by Heap based on certain properties of the event, such as target text.
Raw and labeled events are included in the list of events on the Explore events page. Look for events that have a Define button in the same row. Clicking this button will instantly create a new event using the suggested label.