It allows to enable/create delivery methods and use them in orders, tasks and contacts. Most of delivery services provide information about changes of delivery status and automatic transition by stages of process will take place, based on the given information. The lists of the cities with delivery service offices are updated automatically, if delivery service supports this. You would need to make output of the field, which reflects the delivery method in order, task, contact, to display one or another delivery method.
You would need to enable required delivery services apps for a full-fledged work.