Usually, only charitable organizations are allowed to conduct raffles, and often a license or permit has to be obtained in advance, before any tickets are sold or advertised.  It is, after all, a form of gambling.  Typically, the application for a license or permit for a raffle will require the details about the organization conducting the raffle, and it's considered a sworn statement:  if you make up a fictional charity so that you can do this raffle, and use that fictional charity on the application, you will find yourself in very deep trouble.