Live Helpdesk can be configured to use DNN Host Settings or you can specify your own SMTP Server to send out email notifications. Remember to update the from name, email, and reply-to address.
Template
You can update Email Notification template in the Shared.resx (\DesktopModules\LiveHelpdesk\Views\App_LocalResources\)
For Example:
Suppose you want to update issue created via Form (Agent Template) then update the Agent_IssueCreatedViaForm.Body field. Similarly if you want to update for User Template then it would be User_IssueCreatedViaForm.Body field.
Note: Refer to Tokens available for the notification templates.
Note: Only local file path attachments (as provided by DNN API) are included in notifications. Files that are saved remotely or on cloud are excluded.