If you mean "producing" physical copies for sale (Self-Publishing), this requires a separate :
: Build a Research Room and hire staff with research skills. Mad Games Tycoon 2
In , producing or "adding a feature" primarily refers to the gameplay and engine features you incorporate during game development to improve quality and review scores . Unlocking Features If you mean "producing" physical copies for sale
During the development process, you will reach a screen to select features: Mad Games Tycoon 2
: On the third page of the development menu, you can select available engine and gameplay features.