You have agents on the portal with a multifaceted functionality and in order to help them reduce the redundancy in typing out each ticket response, you could guide them to set up canned responses on the portal. Please ask them to click on the gear icon that says "settings" where they could add canned responses which they could use.
If you believe that an agent could create common canned responses for others in the team, then we do have a feature called roles available from the Estate plan which would allow you to give the agent the permission to edit canned responses. It is generally not available for agents as it is the responsibility of the admin to maintain and prepare canned responses for all the agents on the helpdesk.