To enable Radius Delivery settings Set your location latitude and longitude.
Then set your delivery area with KM
Set the not found message if delivery is not available then the customer will see the message.
How it works?
-> On the checkout page, when a customer selects cash on delivery it calculates the distance between the customer's current location and the restaurant's location. if the distance is within 10 KM then the customer can able to order otherwise they will get a message.