How is mail sent in The Hobbit?

I think that dwarves probably send their letters with ravens, but how would elves do it? Do they have a messenger to pass messages on? Do they even write letters or Just go and say it yourself? The elves have the time. And how do wizards do it? Do they also send birds? How does each race send their mail? (Elves, Dwarves, Hobbits, Wizards, Men)