If you have added the zone, you may skip the steps to 3.
1. EasyStore Control Panel > Settings > Shipping> Add Shipping
2. Select how you want the charges to be calculated (Recommended Flat rate per order)
3. Choose the country > Determine shipping by province/zip code
4. Insert Cash On Delivery as the Courier name> Choose the calculation method (any method will do) > Enter the rate (It can be $0) > Save shipping
Payment method needs to be added.
Settings > Payments > Add payment > Bank Transfer
Amend your instruction for COD customer (Refer to GIF image below).
Display at the checkout page for your customers.