SHEIN offers FREE Standard Shipping (6-8 days) for all orders over $49 to the US.
Otherwise, Standard Shipping is $3.99.
SHEIN offers FREE Express Shipping (2-3 days) for all orders over $99 to the US. Otherwise, Express Shipping is $12.90.
For more info on Shipping and Shipping costs, please see here.
In Modalyst, you can opt to add the Shipping Cost into the Price of your items when importing into your store. That option can be found within your Pricing Rules.