Automatically lock screen of Chromebook when lid is closed

You can get this option by following these steps:

  1. Sign in to your Chrome device.
  2. Click the status area in the lower-right corner, where your account picture appears.
  3. Select Settings and Help and find the "People" section.
  4. Use the "Require password to wake from sleep" check box to adjust this setting.

Now each time your Chromebook goes to 'sleep' you will need a password at the lock screem.