What is commercial use and which companies do not fall on this category (e.g healthcare)

Hi Yiorgos, unfortunately there are no categories/lists which would subtract any company category from obtaining the product license.
eM Client is free for home/personal use only, and every company that want’s to use the application whether for internal communication or business use has to purchase a license for the product.

However we do offer discounts for e.g. non-profit companies etc., for more information about licensing policies and discounts for your company you can contact our sales department at sales@emclient.com

Thank you,
Paul.