Hello @mysarojane thanks for your post. When you are designing your emails, you'll see the ability to customize that footer in your email. If you click in that section of the email builder, you can add your specific info to those icons. So if you have a Facebook, or other social media for those icons, you can add that info. If you DO NOT have a twitter or any of the other social media icons listed there, just leave blank. It should not show up when you send the email. You can test this by sending a test email to yourself prior to sending the actual email campaign. I hope this helps answer your question.
See this Best Answer in this thread for more info.
Note, the same is true for your website. see this help article.
