The Lanvernite Succession
A sending tablet is a magic item, keyed to an individual person, its owner. The creator of a sending tablet can send written messages to the tablet, no matter how far away the tablet is. However, this process consumes extremely expensive material components, with costs increasing with distance and message length. The sending tablet can be loaded with messages at no cost if the sender has physical access to the tablet.
The owner of a tablet knows when the tablet has a message waiting on it, due to a faintly perceptible glow and hum detectable only by the owner. The message is shown on the tablet when its owner picks it up, and disappears forever when the owner puts the tablet back down. If the owner dies, there is no way to retrieve messages from the tablet unless the owner is somehow brought back to life.