How can I email all those who have submitted a form already?

I need to email all the participants, is there a way to do that within Jotform or do I need to email them separately?  

Please try using the Email Newsletter App. This app lets you send an email to people who completed your forms. Here's the link: https://apps.jotform.com/app/email_newsletters.

Hope that helps. If you have any questions, let us know. Thank you.