How can I change the email address for sending autoresponders.

Also how can I change the email address that my customers see when the purchase from my form from noreply.jotform to my business email? Can I do this?

If you want to use your own email address instead of noreply@jotform.com, you can do it with your SMTP credentials: https://www.jotform.com/help/244-How-to-Setup-SMTP-for-a-Form

Let us know if you need more help.