Gelato is a fully white-labeled solution. As such, we don't send any information directly to your end customers.
When your orders are marked as shipped, we will forward shipping information along with the tracking number to Wix. Tracking codes and shipping confirmation emails can be sent to your end customers automatically through Wix.
You can read more about tracking numbers for your Wix orders and see how this will look like for you in Wix's Help Center article Adding a Tracking Number to a Store Order.
You can also check the status of your orders as well as the tracking links in the Gelato Dashboard.