This topic hasn't had it's own thread yet, as far as I know.

I think missions will be handed out by the Council of nobles (for a Maonarchy) parliament (For a Constitutional Monarchy) or by the Senate (for a Republic.)

Additional missions might be handed to you by companies such as the East India Trading Company.

I would like to see missions in the game again, possibly with succesful completion netting you money or prestige rather than useless units.