To add and use voice notes in OneNote for Mac:

1. Choose the ‘Insert’ tab, located at the top of the OneNote page.
2. Select the ‘Record Audio’ option.
3. When ready, click ‘Start Recording.’
4. When finished, click on ‘Stop.’
5. You can play/repeat your recording by double-clicking on the voice note.
6. You can also open the voice note in an external program using the ‘File’ tab.