This list contains all work types you perform for your clients. It could be translation, proofreading, DTP, etc.
Service type is used when you add a new detail row to the project. When setting default rates, you can select different service types as the basis for the rate. For example, translation usually counted on per-word basis, while proofreading tasks are counted on per-hour basis.
You can select Default unit for each service type. This unit will be automatically pre-selected during creation of tasks in translation jobs.
Exclude from scheduling checkbox allows to exclude tasks with a specified service from allocating them in the vendor's workload planner, which is filled when you create translation assignments.
In addition to setting default rates, work types are used to calculate different stats of your performance.