ChanServ has nothing to do with mIRC, and there are different ChanServ's on different networks (i.e. they have different abilities and options). Please realise some networks don't even have services, and they are not a part of IRC or mIRC.
For the best help it's best to go to the network's #help channel or check out their website. If you're on DALnet, it does not have that kind of option.
You may also try using:
/chanserv help
/msg chanserv help
Hope that helps :-)
Regards,