What is a Transport Management System?
Most carriers can provide a web portal or desk top software solutions for you to use.
If you have multiple transport carriers this might not be a long term solution. Your warehouse will end up with many individual systems and not be able to quickly select the best service for every order.
Basically a transport management system will automate many carriers into one solution and provide the sort of things you need when sending goods out of the warehouse.
From track and trace to reverse billing you are only limited by how you wish to use the solution and integrate it in to your process.