During creation of workflow, the objective is to provide you with the basic tools to create a workflow as quickly as possible. We provide a small set of field properties so that the user is not overwhelmed.
Once the workflow has been published, you may edit the properties in the Control Center. Select the workflow and process stage and then click on the fields icon. Select the Edit Field property for the field you wish to edit. This will open the detailed field properties screen.
Select the value of Yes for both the Is Mandatory and Is Unique properties. You may edit other properties based on your requirements.