Where are shipping rates names fetched from?

The app fetches all the shipping information from Shopify using its Shopify API. All the shipping information needs to be configured previously in Shopify. 

When manual shipping rates are configured, the name given for that specific configuration will be displayed as the Shipping rate name by Shipping Rates Calculator+. That name is configured in your Shopify admin:

If you want to modify this shipping rate name, go to your Shopify admin, click on ' Settings' and then 'Shipping and delivery:

All the shipping zones which you have configured will be displayed:

Click on the 'Edit' button on the right side of the respective shipping zone. Now you will be able to see the shipping rates which you have configured, like the example below:

You can click on the Edit button on the right side to modify it. Names that are configured here will be displayed as your shipping rates name, both by the Shipping Rates Calculator+ app and the Shopify checkout. 

Note: only names for the manually configured shipping rates can be changed. For carrier-calculator shipping rates, we will not get any option to change the shipping rates name.