Twig is just a way to render the HTML. The content is determined by the page.
The appearance of the HTML in the browser is determined by the CSS of the theme.
So I suggest breaking down the problems into
1 - Have the page generate the HTML you want
2 - Style that HTML with CSS
Seems you're using the Antimatter theme, so the features module Twig is https://github.com/getgrav/grav-theme-antimatter/blob/develop/templates/modular/features.html.twig
You can see it checks in the page header for the features definition. That's where it checks for the icon, and the rest of the content.
It looks for a FontAwesome icon, so that's not working if you want to add an user avatar. You'd better copy this twig, rename it as contacts.html.twig and add your own HTML.
When starting out, it helps writing the HTML directly in the twig, then looking at a way to integrate it in the page header, so the content can be dynamic instead of hard-wired in the twig.