Posts in the Extra Theme are followed by a “sharing” section which lets users easily share your posts to the main social networks. As you see from the image above, these icons are preceded by the text “Share:”. If you’d like to remove this text (but leave the icons themselves), you can use the following CSS:
Remove the “Share” Text on Posts
To add the CSS code to Extra, paste it into Extra's custom CSS box, which you can find from your WordPress admin menu at "Extra > Theme Settings > General > Custom CSS". Paste it after any other code already in there.