How to edit the finish page after registration?

How to edit the finish page after registration?

How to automatically to send the successful email? 

By finish page, I believe you are referring to the "thank you" page or message that is shown to the user when they submit your form. Please take a look at the following guide on how to set it up:

https://www.jotform.com/help/211-Setting-Up-the-Thank-You-Page

If you also want to send an automatic confirmation email to the person who filled out your form, you can simply set up an autoresponder:

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

If you also want to receive a notification email to your own email address when someone submits your form, you can set up an email notification for yourself:

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

Please let us know if you need any further clarifications or guidance, we are here to help. Thank you.