You have to be at least 18, be member for at least 1 year and be "in the good side" of Chess.com (don't be banned, not be a gigatroll)
https://www.chess.com/blog/KobraBytes/the-chess-community-needs-you
The real question is “why do want to?” The mods are a very helpful lot, but take a lot of nonsense from too many around here. They all deserve more than what they get, in my opinion.