The WPResidence has 2 buttons that becomes visible when you scroll the page. One of these buttons is a contact button.

When you press the button a contact form is appearing. The contact form is displayed via a javascript event that is in control.js

$('.contact-box ').click(function(event){

*** the contact form is already inserted into the page (the code is in footer_buttons.php ) but hidden via css( class hidden from boostrap).

After the contact form appeared you fill it with details and you want to send the message by pressing the send button. The message is sent via ajax actions .

The javascript event for this is at control.js  while the php function that actually send the email wpestate_ajax_contact_form_footer(), is in ajax_function