This is an accepted solution.
Eunice here from Shopify. Thanks for posting and a very warm welcome to the Community!
To enable carrier-calculated shipping we'll need to access your account. While we’re not able to provide account-specific support via the Shopify Community at this time, we’d be happy to continue assisting you through live chat, email, or callback. Please visit Shopify Support and log in to your account to create a support request.
Since this is the next step I've marked this reply as the solution for the benefit of others who may discover this topic. Thanks!
A Shopify Support Advisor will need to add the carrier calculated shipping rates feature to your plan. To connect with a Support Advisor via the helpdesk please follow my instructions below.
1. Head to the Help Center and log in to your Shopify account:
2. Once you're logged in you'll see this page:
3. Before you continue from here, please watch this quick video. This will show you how to select the chat, email, or callback option to connect with a Shopify Support Advisor to raise a support request.
Hope this helps.