1. Open Delivery Rates - Zipcode, click the tab of the state and press Add zipcode in <State>.
2. Enter the Zip Code (up to 20 characters).
3. Optionally enter the County.
4. Choose the Delivery Route – this is mandatory; otherwise you get Error: Please select a delivery route from the dropdown.
5. Set Tax Percentage (-1 to use the state tax) and the Default Delivery Price.
6. Optionally add Dynamic Delivery Price rows (cart subtotal threshold → delivery rate).
7. Under Allow on, tick the order modules that may be delivered to this zip (all are on by default for a new zip).
8. Click Save. You are taken to that zip code's route list with a Done! banner.

The same zip can be added again with a different Delivery Route – each zip + route combination is a separate entry.