A handy little feature in Windows 10 is the ability to turn off your laptop display with just the press of the physical power button.
Turning off your display is particularly useful if you want to quickly lock your computer before you step away from your desk. Just hit your power button to turn off the display, and it will automatically lock your computer. When you return, you’ll have to enter your Windows 10 password before resuming what you were doing.
If you prefer not to have to enter your password go to Settings > Accounts > Sign-in options. Under Require sign in select Never from the dropdown menu.