When someone fills out a form online, do they get a receipt that it has been received?

By default a notification is not sent to the user.

To ensure the user gets a received confirmation you will need to add an autoresponder email, also ensure that the form has a field for collecting the user email so that we can use the field in the

Kindly read more about setting up autoresponders in this guide.

http://www.jotform.com/help/26-Creating-a-Form-Autoresponder