If you used the Power Store, or Power CMS table presets, there is a column for UserGroupID
if you used the Simple registration, there is no User Group column as it is intended for a simplistic registration system without the concept of User Groups.
you can always edit the table and add a user group column if you need one and it does not exist.
the application presets are not intended as a finished project, they are intended as a starting point.
the UserVerificationCode column is intended for use with double opt in registration: