The type of event that you are creating. This is the name of the event that will show in the Postscript application. Note: when creating this event, we will automatically prefix your partner/shop name in front of the event. For example, if sending an event called "OrderPlaced", we'll show it in our UI as "[Your Partner/Shop Name] - OrderPlaced" to distinguish it from others of a similar name. We accept the follow characters in the value field: lowercase letters (a-z), uppercase letters (A-Z), digits (0-9), and underscores (_).