how can do i send an email to all people who have submitted forms?

Emails are sent to the people who submitted the form via email autoresponder. I checked your form and I see there exists already an autoresponder email alert.

To know more about autoresponders, please check these guides:

https://www.jotform.com/help/30-Explanation-of-Email-Notification-and-Autoresponder-Settings

https://www.jotform.com/help/26-Setting-Up-an-Autoresponder-Email

If you have other questions, please let us know.

Thanks.