I guess you mean the motd? 
In arcemu-world , open with notepad, find :
Code:
<Server PlayerLimit = "100"
Motd = "CHANGE THIS!!! THIS IS MOTD! "
SendStatsOnJoin = "1"
EnableBreathing = "1"
SeperateChatChannels = "0"
CompressionThreshold = "1000"
QueueUpdateInterval = "5000"
KickAFKPlayers = "0"
ConnectionTimeout = "180"
RealmType = "1"
AdjustPriority = "0"
RequireAllSignatures = "0"
ShowGMInWhoList = "1"
MapUnloadTime="0"
LimitedNames="1"
UseAccountData="0"
AllowPlayerCommands="0"
EnableLFGJoin="0"
TimeZone="0"
Collision="0"
DisableFearMovement="0">
And change the one I "highlighted"

I might not be right tho,
^^