We are using Contact Form 7 plugin for this theme, It’s one of the best contact form plugin for WordPress.
You can use default form that comes after installing this plugin or you can use or customize form like the demo.
Go to the Contact > Add New. Here you will see a default form code like the screenshot bellow.
Replace the form code by the code bellow, it will make the form like your demo.
For contact form :
Save the form. In the king composer addons you will see the contact form 7 element. Edit the element in the form select dropdown select the form that you created few minutes before.
The output of the contact form is given in the screenshot below –