You can create a username and password specifically for logging on to the device, but Windows 8 works best with a Windows Live account. This works in much the same way it does on many smartphones and tablets.
You enter a Windows Live username and password, and the device is personalized with your settings and Metro apps. It remembers the usernames and passwords for any services associated with your Live ID and automatically signs in, so you immediately have access to your mail, calendar, contacts and social feeds, documents and photos stored on SkyDrive, instant messages, and more. This is a great feature for people who work on multiple devices.
You can replace the password with a picture log-in, which is a custom pattern of dots, lines or circles you draw on any photo.