What is a difference between auto -responder and notification?

Notifiers are emails that will go to you when your customers fill your form. On the other hand, Autoresponder is an email that your customer will receive to email that they typed in your form.

Each of them can be customized, meaning you can change the body of the email that will go either to you(Notification) or to your customers(Autoresponder).

You can check more about them on these links: Notification & Autoresponder.

Hope it helps.