Thanks for connecting with us and sharing your question. Typically, social media icons live under your theme's settings. For the Venture theme, these can be found under Admin > Online Store > Themes > Customize Theme > Footer > Theme Settings.
I also took a look at your website, and I can see you've already enabled 7 of the 8 available social media icons in your footer, so perhaps you are looking to custom code more options into your theme? If this is the case, I wanted to point you towards a published tutorial on adding social media icons via assets.
I trust that helps, but let me know if I missed anything.
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