As you progress in the game, the chosen initial conditions can be changed. After that, you put the characters into a real Sims life where they can meet other Sims, go to work, attend parties, and so on.
Moreover, it is not only about the appearance, but also about the character, about preferences, about a hobby and the chosen values of life. As all the games by this name, The Sims 4 allows you to create the Sim character and customize him or her as you wish. The Sims series is the legend in the simulation video games genre.