This option is found when viewing an issue. To find it, navigate to the 'Issue Actions' menu, click 'Task,' or 'Convert to Project.'
This option refers to the individual who first submitted the issue to the system. The 'Allow User to have access to this task' box will add the individual to the project team, if he/she is not already part of the team. Workfront will also make that primary contact the project owner unless a different name is entered into the project owner field (for project conversions).
The main purpose of this option is to allow team members submitting requests to a queue to continue to view the status and progress of their request.
The Task Preferences has a setting that allows system admins to set Primary Contacts to have have access when converting by default.