Showing Notifications
To show a notification, simply get the notification subsystem and call Show Notification with the correct properties. To check what all the properties do in the system refer to Notification Properties.
UNotificationSubsystem* NotificationSubsystem = GetGameInstance()->GetSubsystem<UNotificationSubsystem>();
FNotificationProperties NotificationProps;
NotificationProps.Title = FText::FromString("Interaction Updated");
NotificationProps.Message = FText::FromString("The interaction widget has been updated.");
NotificationProps.AutoDismiss = true;
NotificationSubsystem->ShowNotification(NotificationProps);
You can also bind events to when the notification is accepted or declined, if auto dismissed neither of the events will fire.