Sending Spell
D&D Description of the Sending Spell : You contact a particular creature with which you are familiar and send a short message of twenty-five words or less to the subject. The subject recognizes you if it knows you. It can answer in like manner immediately. A creature with an Intelligence score as low as 1 can understand the sending, though the subject's ability to react is limited as normal by its Intelligence score. Even if the sending is received, the subject is not obligated to act upon it in any manner.
Deeper info on this Dungeons & Dragons Sending Spell
Note: Add a Reply about how you have applied the use of the Sending spell in a previous Dungeons & Dragons scenario.