Is it possible to send an email to everyone who submitted a form?

Is there a way I can send a blanket email to everyone who has already filled out the form?

JotForm has a reply function that will help you to send an email to all those who submitted your form: 

However, the functions has limits, they are described below: 

-EMAIL REPLY/FORWARD  SUBMISSIONS LIMITS

MAXIMUM FORM BUILDER EMAILS per DAY (Covers the following function: “Reply”, “Forward”, “Test Emails” and “Share via Email in Publish”) :

PAID accounts : limit is 1000/day

Free and Guest accounts  :  20 /day

I would recommend you instead to create the template and send the email from your email provider, you could get only the info submitted in the email field on your form through a report. 

Here are some reports that may help you: 

https://www.jotform.com/help/105-How-to-Create-a-Grid-Listing-Report 

https://www.jotform.com/help/209-How-to-Create-an-HTML-Table-Listing-Report 

https://www.jotform.com/help/101-How-to-Create-an-Excel-Report 

Reports allow to select the desired fields from your form to be included, that would help you to create the recipients list and easily send the email. 

I hope this helps.