For social media icons and other icons in theme I am using Genericons: http://genericons.com/
Unfortunately, there are no flags between them.
However, you can follow these steps I explained on how to add phone number underneath social media icons: https://colorlibsupport.com/t/hot-to-add-text-under-social-media-icons-in-travelify-theme/
Some tweaks are required but you will get an idea on where and what to do.