Windows Hello is a next generation authentication log in mechanism for Windows. Currently one needs to only enter the password in order to login. And some laptops with fingerprint readers can also authenticate based on the fingerprint of the person.
Very soon one could use facial recognition in order to authenticate. Windows Hello is based on that technology. It would use the Iris of the person as an authentication measure. So the only requirement is that you need to be in front of the laptop in order to do this and that is what you do even now. Once the computer verifies you are the same person you are logged in automatically.
One key point to note is that it this feature is solely for the Windows 10 Operating System.