Setup your Shopify Shipping Zones and enable Postcode Shipping Rates
Once you've created your Shipping Zones in the Postcode Shipping app, you'll need to setup your Shopify shipping settings so that your store receives the Rates you create in Postcode Shipping.
To do this you'll need to create Shipping Zones in Shopify and select Postcode Shipping as the rates provider.
Even if you already have your Shipping Zones set up in Shopify, you'll still need to enable Postcode Shipping as the rates provider, so follow along with this guide.
Set up Shipping Zones in Shopify
From your Shopify dashboard, navigate to Settings > Shipping and delivery.
Click Manage Rates.
Scroll down to the 'Shipping to' section.
Here you will add Shipping Zones which reflect those you have set up in Postcode Shipping.
Notes: If you already have your Shipping Zones set up from before you installed the Postcode Shipping app, you can work with the Shipping Zones you already have. Skip to the next part, Enable Postcode Shipping Rates, below.
Click Create Shipping Zone.
Give your Shipping Zone a name and select the countries that will make up the Shipping Zone.
Click Done when you are ready.
Make any other Shipping Zones you need.
With your Shopify Shipping Zones setup, you need to enable Postcode Shipping as the rates provider.
Click Add rate on the Shipping Zone you wish to enable Postcode shipping for.
If you already have rates set up from before you installed the Postcode Shipping app, delete these and add a new rate.
Next is the important part. Choose Use carrier or app to calculate rates, and select Postcode Shipping (Rates provided by app).
Do the same for any other Shipping Zones.
Note: you'll only need to do this once for each Shipping Zone, as you're not actually adding rates, you're just connecting the Shopify Shipping Zones to the rates you've already created in the Postcode Shipping app.
The last thing you need to do is Save your changes.
Now you've setup your Shopify store to automatically use any Rates you create in Postcode Shipping. If you haven't already done so, go ahead and create your Shipping Zones, Regions and Rates in Postcode Shipping.