You have many options for shipping in an eCommerce
Shopping Cart (not all may be available - depending on script using):
-- Per item
-- By weight
-- By Size
-- Fixed price for all items
-- Fixed price for items in certain categories
Depends on what your selling and to what country?
User enters postal address on purchase, you ship their items to that address via: RoyalMail, ParcelForce, ect.
Some eCommerce websites allow you to enter a tracking number so the user can view it from their account at your store.
What script are you using?