What are Request Participants
Request participants are customers and organizations who can view, comment, and receive notifications about a request. Participants receive the same notifications as the reporter and can turn off notifications at any time. You might add request participants so they can provide more information about a request, or to notify them of a request's progress.
To add a participant to a request:
Open the issue you want to add a request participant to.
Select the Request participants or Organizations field on the right side of the issue view.
Enter the participant's details, then click the tick.