Event names must be 40 characters or fewer, can only contain alpha-numeric characters and underscores, and must start with an alphabetic character.

An event allows you to measure a specific interaction or occurrence on your website or app. For example, you can use an event to measure when someone loads a page, clicks a link, or completes a purchase, or to measure system behavior, such as when an app crashes or an impression is served.

How Do I See Event Parameters in GA4? Within the GA4 standard reports, the simplest way to see your event parameters is to first look at a list of your events. You can see this below where I've clicked into the “Events” report, which is within the “Engagement” reporting section on the left-hand navigation.