When orders are updated with a tracking number and set to shipped status in your store, your shopper will see a link on their order (and confirmation emails) inviting them to track the progress of their shipment.
However, in order to function correctly, the shipment tracking absolutely requires the following:
The order must have a valid Tracking number which is typically provided to you by the shipping carrier when the shipping label is generated.
Shipping Carrier Credentials
Your Shift4Shop store must be properly connected and configured for use with the tracking number's respective Shipping Carrier.