Sound/ Audio

1. Click the down arrow next to Annotate

   

   button in the Toolbar to reveal the tools.
2. Select the Sound tool

   

   .
3. Click on the page of your document. In the menu which appears either record a note or annotation by clicking the red record button, or select a file on your computer which you have previously recorded.

Once added, click on the sound/ audio annotation icon on the page to listen to the recording.

Note: Not all PDF apps support audio annotations. A PDF re-saved in an app without support for this feature will erase the annotations. This includes Preview in El Capitan and earlier.