There is no software available to install to file emails to NetDocuments from Outlook on a MAC.
The ONLY option available is to consider deploying the ndMail feature to Office365. This puts ndMail in All versions of Outlook 365 being Desktop (Windows),
- and Mac.
This version of ndMail is a WEB panel that can then be exposed to all users or selected users via your Office 365 admin interface.
Here is a link to the instructions on how to deploy to office 365 centrally - after installation you can then make it available for certain users/groups.
Please note that if you push this out then it will also appear on Outlook for WINDOWS as well which may cause confusion with users who have the 'installed version' for windows as well as the 365 version.
But the value is that now users can save emails from Outlook on the Web, Outlook on Mac, Outlook on Mobile.
Saving emails is as simple as highlighting the email, selecting in the top right hand corner of your Outlook, search the workspace that you want to file the document in and click File.