You can send the email notification in Schedule from the appointment or service call window by choosing the Notify Customer 
icon or by right-clicking the appointment or service call and then choosing Notify Customer.
For more information about Standard and Advanced Communications, see Event Trigger Notifications in Signature Agent documentation.
Standard notifications
Appointment cancelled
Appointment created and scheduled
Appointment reassigned
Appointment rescheduled
Technician arrived
Technician checked out
Service call created
Service call created by ESMS email
Advanced communication HTML notifications
Technician arrived
Technician in Route (Dispatched)
Appointment Completed