Try as described here: Is openhab 3 multiuser? - #5 by Udo_Hartmann
openhab> openhab:users add udo mypassword user
udo (user)
User created.
openhab> openhab:users list
openhab (administrator)
udo (user)
openhab> openhab:users remove udo
User removed.
openhab>