Email notifications for surveys
When an administrator creates a survey and assigns it to a user, an email notification is sent to the user. Selecting the survey link in the email notification redirects the user to the survey page, where the user can take the survey. This type of survey is called a non-triggered survey.
Triggered surveys are sent when a defined trigger condition is met. When the condition fires, an event is created and placed in the event queue. This event automatically invokes the base system Survey Invitation notification, which sends an email to the assigned user. You don't need to create event, as the survey invitation notification is preconfigured for this purpose.
Base system Survey Invitation notification
ServiceNow includes a pre-configured Survey Invitation notification for surveys. When a survey is assigned to a user and a non-triggered or triggered condition fires, this notification sends an email to the designated user. You don't need to create event or notification.