Basic Rules, pg. 259
Message
0-level (Cantrip) Transmutation
Casting Time: 1 Action
Range/Area: 24 sq.
Components: V, S, M
Materials: A short piece of copper wire
Duration: 1 Round
Damage/Effect: Communication
You point your finger toward a creature within range and whisper a message. The target (and only the target) hears the message and can reply in a whisper that only you can hear.
You can cast this spell through solid objects if you are familiar with the target and know it is beyond the barrier. Magical silence, 30 cm of stone, 3 cm of common metal, a thin sheet of lead, or 2 m of wood blocks the spell. The spell doesn't have to follow a straight line and can travel freely around corners or through openings.
At higher levels: The spell's range doubles when you reach 5th level (total of 48 sq.), and again at 11th level (total of 96 sq.) and again at 17th level (total of 192 sq.).
Available for: Bard, Sorcerer, Wizard, Artificer