Elle here from Shopify.
Shipping rates are independent of the theme you're using, so if there are no shipping rates populating in your checkout, this is likely due to not having any shipping rates set up under Settings > Shipping.
Here is our doc on how to set up Shipping rates for your reference.
I'd recommend offering Free Shipping if you're able to! If not, perhaps consider offering Free Shipping over a certain dollar amount. These strategies have proven to help increase conversion rates and average order value.
Let me know if this helps! Happy to answer any other questions you have.
|an hour ago|