2. Then check the location of this notebook and get its folder: right-click on notebook in notebooks tree > Show in Finder for local, Dropbox or Box notebooks; and Properties for iCloud and WebDAV notebooks.
Show in Finder reveals the containing folder of your notebook.
3. Select the folder of your notebook > compress it > send to the recipient.
Share the section with Windows OneNote users
1. Check the format of the whole notebook: right-click on the notebook in notebooks tree > Properties > Format. It needs to be OneNote.
2. Reveal in Finder the folder of this notebook > open the folder > select and send the .one file of the section that you want to share.
Share the local notebook with Windows OneNote users using cloud storages
Windows OneNote users can sync the notebooks through Dropbox, Box and WebDAV mounted folders too. You can use these storages to easily share your local notebook.
Just place the folder of your notebook to your cloud storage folder in Finder and share the folder using storage web client.
If you want to share the local notebook with someone who uses OneDrive for syncing OneNote notebooks, upload the notebook to OneDrive. Additionally it's the only way to share the notebooks with Mac and iOS OneNote users.
As soon as Mac OneNote doesn't allow to store the notebooks locally and upload the local notebooks to OneDrive from Mac, the only way of moving the local Mac Outline notebooks to OneDrive is to create a new notebook on OneDrive and to move all the sections from your Outline notebook to this new OneDrive notebook.