Workflow Templates are saved definitions of one or more workflows which are shared among all portals in a Portal Group. You can always create individual workflows in each portal manually on as needed basis but if the workflow you need is the same for all portals, defining it once will save you a lot of time.
We are in the process of building a workflow template library to make it easy for your to import and adjust ready-made workflows (examples include client or employee onboarding). Feel free to contact us to suggest a new addition to the library, we will be more than happy to analyse your requirement.
See this article to see how to create a Workflow Template.