Hello,
When you install the plugin for MIM you get the major incident and the communication task with it.
Now for Major Incident you will get separate application and module in navigation but it redirects to the Incident table itself:-
Now as you correctly mentioned any ITIL User can Propose a major Incident by using the Propose UI action however only users with Major incident role can promote or demote a Major incident.
On the incident form you will see the workbench option only if the incident has been proposed a Major.
Now you can configure communication task which will basically send out communication manually or automatically based on how you set it up.
So when a Incident is marked as Major incident the incident communication task comes into picture where it will automatically make the agent to send the communication within a set timer otherwise it will show it is due.
To find more information please check the below article:-
Please mark my answer as correct based on Impact.
