How to Use a PIN Instead of a Password in Windows 8 - How-To Geek

Entering your full password on a touch screen device can really become a pain in the neck, luckily for us we can link a short 4 digit PIN to our user account and log in with that instead.
Note: PIN codes are nowhere near as safe as using an alphanumeric password, however, they do still have a purpose when you donít want to enter your 15 character password on a touch screen device.
Creating a PIN

Press the Win + I keyboard combination to bring up the Settings Charm, then click on the Change PC settings link.