How do you add a sim in the Sims 3?

Answer 1

After you have started the game, the ways to get an additional house member are by "trying for a baby" in bed, convincing a friend to move in, or by adopting over the phone. There is no way to make your own character unless you make another character, place them in a house in your town, then make them marry one of your main house characters or simply move in as a good friend.