Since most people were illiterate in the Middle Ages, most communication was verbal. If a person needed to send a message to someone in another town, he could hire a courier, who would memorize the message and deliver it orally.
Written letters were considered formal correspondence and were rarely used by common people. Even if the sender and recipient were literate, the only method of delivery was hired courier, which would have been expensive. There were no newspapers, so people heard news from beyond their own village only by word of mouth. Official proclamations from the local landowner were often read aloud to the townspeople in churches or other public places.