You can use the help command (/?) to see how another command is used:
/? micon
Code:
ALIASES:
/macroicon, /micon
USAGE:
/micon "icon name" [category]
→Displays the specified icon as a hotbar icon. If used twice in a single user macro, only the first instance will be recognized.
>>Categories:
action
If the icon name is an
action, action recast time
and required MP will
be displayed with the icon.
blueaction
If the icon name is a blue
mage action, action recast
time and required MP
will be displayed with the
icon.
pvpaction
If the icon name is a
pvp action, action recast
time and required MP will
be displayed with the icon.
general
If the icon name is a
general action, action
recast time will be
displayed with the icon.
emote
If the icon name is an
emote, its icon will be
displayed.
companion
If the icon name is a
companion action, its icon
will be displayed.
pet
If the icon name is a
pet action, its icon will
be displayed
minion
If the icon name is a
minion, its icon will be
displayed.
mount
If the icon name is a
mount, its icon will be
displayed.
enemysign
If the icon name is an
enemy sign, its icon will
be displayed.
waymark
If the icon name is a
waymark, its icon will
be displayed.
gearset
If the icon name is a
gear set number, its
icon will be displayed.
classjob
If the icon name is a
class or job, its icon
will be displayed.
quickchat
If the icon name is a
Quick Chat message,
its icon will be displayed.
Category defaults to action when none is specified.
Only micons that fall into these categories can be used.