If you're using a Windows tablet, convertible notebook or smartphone, Windows 10 can morph to fit your screen. It's a new feature called "Continuum."
When Windows senses you're not using a keyboard and mouse, it will enter "tablet mode," featuring a simplified task bar that just has a Start button, Cortana and app switcher. An expanded Start Menu is your default home screen in tablet mode, and all apps automatically appear full screen.
You can also force your PC in and out of tablet mode by clicking or tapping on the tablet mode button in the action center.
It's still a little buggy -- it currently resizes all your Windows incorrectly when you go back into "desktop" mode. It also doesn't show any apps on your desktop in tablet mode. Let's hope that changes before the final release.
