How to capture email addresses?

How can i capture email addresses of those who respond to compare it with my outgoing invitation list?

Hello,

I have checked your account and your form named "Chamber of Commerce 2014"

I have seen that you have a hidden email field in your form as you can see the following screenshot. 

You can make it appear on the form and let it fill by the users. Also, you can set it as "required". So that, you can also see the emails of the users who fulfilled your form in your submission list.

Moreover, I have seen that you do not have an autoresponder in your form. You can set autoresponder emails to your form. So that, your users can receive an email regarding that they have fulfilled your form. Please check the following document related to setting up the autoresponder emails: https://www.jotform.com/help/26-Creating-a-Form-Autoresponder

Furthermore, you can check the whole email activities in the Activity Logs of your account as you can see the following screenshot:

Here, you can see all of the notification and autoresponder emails that sent from your forms or failed to sent.

Please check the following documents below for further detailed information related to activity log: 

https://www.jotform.com/help/370-How-to-View-Your-Account-Activity-Logs 

https://www.jotform.com/help/293-How-to-View-All-Your-Form-Email-History

Please check them. If you need further clarification, let us know. We will be glad to help you.

Thanks in advance.