How can we determine who has the authority to 'Send' communication from the Major Incident Workbench? Is it only the "Major Incident Manager" role?
Release or Environment
The users with the below roles will be able to see the send UI Action under the communications tab in the Major Incident Workbench. Also, they are able to send the email communications
Provide users with the above necessary roles in order to view Send UI Action for sending the communications of a major incident.
Major Incident workbench — the Communications tab - https://docs.servicenow.com/bundle/orlando-it-service-management/page/product/incident-management/concept/mi-workbench-communications-tab.html