How can I change the email recipient address?

One more thing we don't know how to change the email that we get the online registration. Can you tell me how we can change that when needed.

Yes, it is possible to change an email recipient address, please check the following guide that will help you doing that: https://www.jotform.com/help/314-How-to-Properly-Add-Change-and-Test-a-New-Email-Recipient-Address 

Let us know if you have any question.