I'd advise you to chat with your system administrator about it.
Please understand that the job role attribute in Workfront is supposed to be used as a placeholder in project templates, because it's a way to indicate that specific tasks will take a certain amount of time. Having job roles as a container for the time allows more functionality such as in resource management or workload balancing. The fact that you don't have a job role might be intentional, unless you were set up in Workfront to be resourced or to gauge your capacity in some way.