you cannot do it

buy or rent mortal kombat enchaind

You must simply buy a specific cheat code device. It's called gameshark.
If you want to get gameshark you can ask for it at your local gaming store.
Or you can browse the internet and order it online.
With it you can get many more unplayables in this game scuh as:
Jax, Young Shujinko, Ghost Liu Kang, Sonya ect.

You must be thinking wrong dude. Kitana is in the game, but she cant be unlocked. But u
can talk to her.