how do i receive the form

when someone submits a form how do i know? 

Submissions will be stored in your Jotform account:

https://www.jotform.com/help/269-How-to-view-Submissions

It is also possible to set up emails when the form is submitted.  These are our guides on setting up email notifications.  The first is on setting up notifications sent to you:

http://www.jotform.com/help/25-Setting-Up-Email-Notifications

The second is how to setup notifications to your users:

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