Click on the Workflow tab --> Business workflow --> Edit workflow, a page as shown below will appear. In this page you can choose the workflow agents you want to include by checking the boxes against them.
"Requester" is a mandatory role for the workflow and hence cannot be removed
Based on the need, you can decide whether or not to use a "Reviewer"
You have to choose an "Approver" or an "Executor" for the workflow to function properly
After configuring the workflow, configure the workflow agents by assigning the different technicians to their respective roles in the workflow
Add conditional rules to assign specific technicians and priority to the task by using "Assigning rules"
Finally configure who should be notified, when they should be notified and with what message by using the "notification rules"
Note:
Instead of using manual requesters the Automation feature can be used to automate the process of raising requests.