Setup > Preferences & Costs > Quote Details > Shipping Cost Type
Shipping Cost Type
Options: Line Item or Distribute
The shipping cost can be calculated with an operation or it can be added manually.
Line Item
The Line Item option will add the shipping cost as a separate line item in the quote.
Distribute
The Distribute option will add the sipping cost to each item in the quote.
Note: the shipping cost will be divided bases on the items true weight.