These icons are directly connected to your social media sites.
You can easily change which ones you want to display and remove the ones you don’t want.
Go to DASHBOARD > APPEARANCE > CUSTOMIZE > GENERAL OPTIONS > SOCIAL OPTIONS.
Copy and paste your social media URLs in the corresponding spaces. If you don’t want a particular icon to show up, just leave it completely blank.
There’s also footer areas 1, 2 and 3 which you can customize using this tutorial.