Currently, Turnitin Feedback Studio (TFS) is set up to allow only one instructor per class through Turnitin.com or TurnitinUK.com
However, a standard TFS class can be converted into a master class with sections to add a TA (Teaching Assistant) instructor per section. For more information about this, please check our Help Guides:
Each section of a master class can only be assigned to one TA; there is no option to assign multiple TAs to one section class or multiple instructors to one standard class.
Note: When using a Learning Management System (LMS*) to integrate with TFS, it may be possible to assign multiple instructors to a TFS class through the LMS. If your institution uses an LMS, please check with your LMS provider whether the feature to add multiple instructors to a class is supported.
*Examples of an LMS include Blackboard, Moodle, Canvas, D2L (Brightspace), etc.