I guess the first big question is what kind of roleplay are you interested in? They can vary hugely in type! Broadly speaking there are three types:
Celeb; where you roleplay as a celebrity/real person. That's the one I know the least about as I've never done it, but it's very popular so I'm sure someone could help you out!
PB/Original; Entirely original characters, or characters made around a certain face. That's often divided into various genres such as historical, or sci-fi or fantasy.
Fandom: similar to fanfiction and the one I know the most! That can be divided into two big categories, the panfandom or the single fandom. Panfandom games incorporated some or all different types, from movies to comics to books to TV and beyond! Some also accept original characters, or original fandom based (for example a future child in a Harry Potter game, or an original Slayer from the Buffy universe.