The story
From voice + note. Late 2010s. Widespread since the 2020s. Predated by a trade name VoiceNote (1990s) for voicemail software; that trade name was not widely used among the general public.
Etymology from Wiktionary, CC BY-SA 4.0.
voicenote
Today it means: An audio message, usually (1) in lieu of an SMS text message or (2) as a note to self in audio form. Full definition →