This adds a new user to the Mac that can be managed with parental controls.
Convert this account to a parental controls account.
This option converts the account you’re currently using to a regular, non-administrator account. If this Mac has only one administrator, you’ll also be prompted to create a new administrator to replace the one you’re converting. OS X requires at least one administrator.
If you want limited access for a user on the Mac, but don’t want to add that person as a user, set up a guest user account that you manage with parental controls. For more information, see Set up users on your Mac.