Before applying to the game, you should definitely read most of the information available on MotM's info files. Once you're ready, the application process for characters requires you to determine what type of character you're applying for. What is included below are the articles and applications directly pertinent to getting a character on MotM.
Feature Character (FC Application)
Most of the characters from the series titles that MotM supports are
already created on the game and already equipped with a set of stats. If
they are part of a preexisting game source and you can finger them, they
are referred to as 'Feature Characters.' Due to the sheer number of
characters available, the old distinction between Core and Supporting
Feature Characters has been removed.
Original Character (OC Application)
These characters are characters created originally for the game by the
game's players. They are known as "Original Characters," and can either
be completely original or inspired by an external source, in which case
they would be referred to as an Homage.
Adapted Feature Character (AFC Application)
Any character that is part of a series supported by MotM but not already
created on the game is an Adapted Feature Character, and requires some
work on the player's behalf to determine how a particular role will fit
in game. They are expected to have a good understanding of the series
implementation and the game theme in general.
Restricted Concepts (Restricted)
These are some of the concepts that are restricted on MotM.
Adaptation Process (Adaptation)
These are the rules, tips and processes for adapting characters to
Pitch Process (Pitching)
This is the process for pitching an original application concept or
character adaptation to staff before submitting a full application. This
is a highly recommended thing to do if you don't like to rewrite a lot.