Can you use the voice annotation feature to record scratch audio?

In other words, can you have the voice annotation play during playback?

As I understand it its annotation only. But you will find the sound file in the root file. That means if you save your storyboard projects to the same file you will be able to access all your annotation directly in storyboard by open this file in the library. Just go to the library window left panel and right click ,choose -Open Library . This will add your storyboard projects to your library. Now go to the project with the annotation you would like to add. Open the package by clicking on it and all subfiles will show.
Annotation is usually at the bottom. When you press it all annotation files will show in the library’s right window. Since the navigation is problematic due to strange naming you will have to drag the files into the timeline and listen to it. Maybe some Toon Boom professionals can give a hint on how to read the naming of the files. The files will not get immediately accessible after recording, only after opening another project or restart the files will show in the library .

Best regards

Voice annotation? I am a little confused. Did you mean that add and create annotation object from audio source? Yes, a robust annotation add-on allows to load and create annotatiob from both image and audio source.