For Amazon orders, you can use the “Amazon - by tracking link” option. If you go to Amazon’s “Your Orders” page in Safari, you can use the Share button and then choose “Add to Deliveries” for a list of shipments you can add. Or you can copy the link of any “Track package” button on the “Your Orders” page and paste it into the text field on the “Add Delivery” screen.
Tracking orders from Zappos is not current supported. If you like you can create an “Other” delivery and add a link to your tracking page, so you can keep track of the shipment manually along with your other deliveries.