OP or operator status, gives you permission to every command in-game. Only assign OP staus to the people that you trust, this will help to prevent griefing.
Type “op username” into the Command Line area of the Live Console. You can continue using this command to add additional players if you wish. If you would like to remove OP status from a player you would type "deop username" instead.
You can give other players OP status in-game once you have given it to yourself by using the /op username command.