Like any other Windows you can create a user and set password for him in Windows 8 too, this user is known as Local user as all details are stored locally in your computer, but Windows 8 also allows you to login using your Microsoft account, this will enable you to sync all settings.
- On your Start Screen click on user and then on Change Account Picture,
- Now click on click on Users from left side and then click on Switch To Microsoft Account from right side,
- Now it will ask your email address and then password, just provide it and you are done. When next time you will boot you will have to sign-in with your Microsoft account.
If you wanna switch back to local account then repeat the same process and instead of selecting Microsoft Account in 2nd step, just select Local Account.