How do i set MLock and what does it mean?

Answer 1

/msg ChanServ SET <#channel> mlock <modes>

MLOCK (or "mode lock") allows you to enforce a set of modes on a channel. All mods added with this command will be kept by the ChanServ

Example:

/msg ChanServ set #channel mlock +ntCT

http://wiki.inspircd.org/2.0/Channel_Modes

Answer 2

/msg ChanServ SET #channel mlock mode
Sets channel mode lock.
MLOCK (or "mode lock") allows you to enforce a set of modes on a channel. This can prevent abuse in cases such as +kl. It can also make it harder to fight evil bots, be careful. Locked modes can be seen by anyone recreating the channel (this includes keys).

Syntax: SET <#channel> MLOCK [modes]

Examples: (some may use modes your ircd does not support)
/msg ChanServ SET #channel MLOCK +nt-lk
/msg ChanServ SET #channel MLOCK +inst-kl
/msg ChanServ SET # channel MLOCK +ntk c
/msg ChanServ SET #channel MLOCK +ntcjf-kl 2:30 #overflow
/msg ChanServ SET # channel MLOCK +mntF-kljf
/msg ChanServ SET #channel   MLOCK +ntlL 40 #channel2