In order for the technician to assist you better, they will sometimes need to be able to see exactly what you are looking at on your computer.  This allows them to personally guide you through various steps per your device.

Enter the code provided to you by the technician.  This will allow him to view your computer screen for this temporary instance
ONLY.  The technician CANNOT access your computer without direct authorization from you, and all access is terminated at the end of the session.