The
Books app is for reading, not document handling.
Use
Pages for sharing annotated documents.
https://support.apple.com/en-us/HT208459
Work with annotations on a Mac:
If you're using iCloud to keep all your Pages documents up to date across all your devices, annotations appear in your document on all your devices. On a Mac, you can remove, show, or hide annotations when editing a document.
To delete an annotation, select the annotation, then press Delete.
To remove all annotations, choose Edit > Remove Smart Annotations.
To show or hide all annotations, choose View > Show/Hide Smart Annotations.