Thank you for your inquiry, in the current version, the contact form fields are fixed, you can request our devs team to customize additional fields or customize the contact form to link to third party plugin such as contact form 7.
Based on Codecanyon support policy here, the off-the-shelf product features come as it is as per item description and live preview page, customization is not part of the support scope, however can be requested to our devs team via the contact form here if needed.