Fiery Messenger

Cantrip (This spell consumes no mana, but can
only be cast if you have at least 1 mana available
of the corresponding color. Only 1 spell with
Cantrip can be active at a time).
Use or summon a small Fire Creature to travel
and deliver a message.

It's quite efficient, just dont give it any letters,
scrolls, or any kind of paper really.