To use the store's Real-Time shipping calculation functions, you will first need to integrate your 3dcart Store with your carrier(s). To do this, use the Left Hand Navigation Menu and proceed to Settings =>Shipping =>Shipping Settings
Once there, you will see a listing of the following carriers at the bottom of the page:
Towards the right of each carrier's listing, you will see a link labeled "Enter Credentials" where that carrier's specific credentials will be entered by you. If you do not have an account with these carriers, 3dcart provides buttons that allow you to register with each respective shipping carrier for the required access.
Note: Some carriers will incur additional charges (from the carrier company) in order to create an account with them.
For more information on setting up your 3dcart Store for Real-Time Shipping Calculation, please review our knowledgebase article located here.