If your device isn't running Windows 10, refer to the Windows 8 instructions.
From the Home screen, navigate: Settings icon (located in the lower-left) > Accounts.
If the Windows Settings options are not visible, tap or click the Settings Home icon (located in the upper-left) to go to the Settings home page.
Utilize the touchscreen (if available) or mouse to select on-screen options.
From the left-pane, select Family & other people.
From the Other people section, select the account that you wish to remove.
From the prompt, select Delete account and data to confirm.