Create-A-Sim is needed to create Sims characters. With no Sims, you can't play the game. Sims 4's Create-A-Sim is easier to use than it is in other Sims games. The Sim's body type can be changed by clicking and dragging parts of the Sim's body. There is a slider to change how muscular the Sim is and another slider to change how fat the Sim is.