Carrier calculated shipping is a feature which is available to you on our Advanced Shopify Plan, a la carte monthly, or for free if you opt for an annual subscription.
Currently this feature is only available to merchants in the USA and Canada using Shopify Shipping. The rates for the courier of your choice (Canada Post, USPS, DHL Express, or UPS) will be displayed on your storefront, and you can purchase shipping labels for each order within your admin at a discounted rate.
You can learn more about carrier calculated shipping here.
If you wish to have this feature activated on your account, please reach out to our support once you switch to annual billing!
Hope this helps!