Firstly, you need to install “ Cf7 Icons and Labels “ plugin in your wordpress dashboard. This plugin can be used to add font awesome icons and labels to the Contact Form 7. This is very easy to use.
Go to your Dashboard and search “Cf7 Icons”. Like below Screenshot:
Then Install and Activate it.
After That Edit your contact form then you just need to add class for icon and placeholder for example: ”class:cf7-fa-icon-fa-user class:cf7-label-full_name”. See below Screenshot:
You can see more icons from here: Click Here – https://fontawesome.com/v4.7.0/cheatsheet/
Check the preview of contact form.