Mote lets you add voice comments to Google Classroom, Slides, and Docs. As of yesterday it lets you add voice comments to Gmail messages. Mote recordings in Gmail can be played by anyone who receives your email. Recipients don’t need the Mote extension in order to hear your message. Recipients who do have Mote installed will be able to reply to your voice message with voice messages of their own.
https://www.freetech4teachers.com/2021/02/add-voice-notes-to-your-email-with-mote.html