Are you still looking for guidance on this? The only library that’s widely used by other peers my professional circle is PHPMailer, you can view that here:
Considering that you’re using what looks like a different library, I assume that you’re wanting to code this out? If so, once you have the form configured and running, you should highly consider form validation, also.
Additionally, I would not recommend anything from CodeCanyon unless you can help it, as not only are they a pain to deal with, but the development standards have slipped over the years. Another two options before I would even think of going down that road are: Contact Form 7 and Gravity Forms.