Object Roles has the following types of roles to inform when you generate a notification.
You can send notifications to:
Resource: Owner of the timesheet. (ex. The timesheet task and hour are associate to a resource, that resource is the owner).
Submitter: Person who make the action in the timesheet (ex. person who send timesheet for approval).
Resource Manager: Resource Manager of the project.
Approvers: Resources with access to approve timesheets.
Editors: Resources with permission to edit timesheets.
Project Managers: Project managers of the project that resources sending hours.