You have several order events to choose from: Confirmed (meaning payment has processed for the order), Shipped (has left the warehouse), Marked Out For Delivery (mail piece has reached the local mailing facility that is going to deliver the package), Delivered (the package is officially in your customer's hands), and Returned (the package has been checked back into the Amazon facility). You can also send messages After Positive Feedback is Left if you have completed the Seller Central Integration.
For the first two order events, Confirmed and Shipped, Feedback Genius does not need any tracking information to be made aware of the events occurring. Messages set to go out on these events will automatically work without tracking information.
However, for Marked Out for Delivery and Delivered Feedback Genius will need tracking information. If your orders are FBA, this tracking information is automatically accessible by Feedback Genius through Amazon's API. In order to send delivery-based messages to MFN orders, Seller Central Integration must be completed.