Before you can start using the Postcode Shipping app you need to make sure that your Shopify Store plan supports the features the app requires.
Your Shopify store will require Carrier Calculated Shipping to use the Postcode Shipping app. This feature is by default included on the Shopify 'Advanced' and 'Plus' plans, and you can also request it to Shopify Support if you're on the 'Shopify' plan.
Some additional important points about carrier shipping are explained in this related article: What is Carrier Shipping and why is it required?
How to check plan type
From your Shopify dashboard click Settings > Plans & Permissions.
Here you can view your current plan.
Updated on: 02/12/2022