You can make the icon go away by turning off the Voice Over feature in Accessibility:

1. **System Preferences** > **Accessibility**  
2. On the left, scroll down to the "Motor" section, then select **Voice Control**
3. Deselect **Enable Voice Control**


 [![Screenshot of the Accessibility Preferences Pane showing the Voice Control options][1]][1]

  [1]: https://i.sstatic.net/Hq6dK.png "Screenshot of the Accessibility Preferences Pane showing the Voice Control options"