How do I make my shopify app a rates provider?

I'm making an app for my shopify store, and I'm searching how to make my app display on the store settings as a rate provider but can't find any information regarding this.

Here is a picture of where I'd like my app to show

To clarify a bit on how to get to the above and what I'm talking about.

Head over to Shopify Settings > Shipping & Delivery
Click on Manage Rates
Select the appropriate Shipping Zone, click on Add Rates

Thanks in advance

Solution

The easiest way to be a carrier in a store is to be an App that installs itself as a custom carrier service. When you do that, the store (Shopify) will send every checkout payload (origin, destination, items) to your App, where you can figure out an appropriate rate and return that to the customer.

So your App means any customer will see your carrier and rates for their checkout. The merchant will see your carrier service in the admin, and they can turn it on/off from their desire as they please.

This is primitive, but it works.