Hello,

There is no default option to add Instagram social icon but there is a workaround.

If you want to use extra social icons in Helix templates, you can use Custom field at the bottom of the social icons list within the Basic tab of your Template Options for it. You need to add the fontawesome class(space)social link.

Example: fa-instagram https://instagram.com

If you want to add more than one social icons, then you need to use any of the default icon and use custom CSS.

For example, to change Dribble icon to Github, you need this CSS

 .fa-dribbble::before {
    content: "\f09b";
}

Note: Path towards custom CSS: Extensions>Templates>Styles> Click on your current default template name then choose Template Options. Then find custom CSS within the custom code.

Best Regards