I can't find "collaborator" in the system. I am using the service desk ondemand

[Charlie Cheng]

This question is in reference to Atlassian Documentation: Managing collaborators

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[Phill Fox]

See this definition from https://confluence.atlassian.com/servicedesk/collaborator-660967501.html

Collaborators are users that occasionally assist agents with customer requests by making internal comments. For example, developers help support staff analyze a bug and add a comment that explains the cause and any workaround available.
Collaborators don't have access to the service desk interface (e.g. queues, reports and SLAs) and service desk projects appear as JIRA projects to them. They cannot work on issues, for example, logging work or transitioning issues.
Collaborators can:

• View issues, comments and attachments

• Add attachments and delete their own attachments

• Add internal comments to issues and delete their own comments

• Watch and vote for issues

A collaborator consumes one JIRA user license.