Adding a mail to button

I failed to understand what exactly you wanted to do. Are you asking how to add an "mailto:" button on your form?

https://www.w3schools.com/tags/tryit.asp?filename=tryhtml_link_mailto

If that's what you mean, you may achieve this using the Text (HTML) Field.

Here's an example: https://www.jotform.com/71096485538972 

1. The first link is designed with CSS to look like a button

2. The second one is just a plain link

You can clone that form so you can have a closer look.

Complete guide: How-to-clone-an-existing-form-from-a-URL 

In case we misunderstood your question, just get back to us with a bit more info and a clearer description of what you're trying to do so we can better assist you.