Work roles are created in the Admin section of Ravetree. Each work role can have a billable rate associated with it. You can create as many different work roles as needed for your organization.
Once you have your work roles set up you can associate work items with work roles. For example, when you create a new work item (e.g., a task), you can assign it to someone with a particular work role (e.g., "Designer"). The billable rate associated with that work role will be multiplied by the time estimate you have entered for the work item to calculate the estimated fee for that work item.