If you want to become a rapper, quite famous, you have to go to a label and show what you can do. There are two options: they will accept you as a trainee for an indefinite period or you have to go to another label for audition. If they accept you, you stay trainee and you can wait up to several years until you can perform on stage. Often, you don't even know if you will be a solo artist or maybe they will get you into a group as a rapper. Once you perform on stage and the label you work for is not famous, you have very little chance that anyone will hear about you at all. If you want to know how it looks more exactly, I suggest you do research