You type it in at the bottom where you search other member's names. Then, a notification will come up saying that you have entered a cheat code and you will get some Koins.
I do not know ALL of the kerpoof cheat codes, but I do know 2.XYZZYH200Kkl
type XYZZY into the searchbox next to "Share by others."
H200Kkl
TYPE XYZZY in the search box called share by others.
press XYZZY
type xyzzy and it should work about a few times it gives you about ten coins
you do drawings
you type cheat codes in like this snow1
there is no cheat codes menu .
moshi cheat codes are codes u type in when you log in 2 moshi monsters
nowhere because there are no cheat codes for halo 3
type one cheat at a time