This is a suggestion for a new feature; I am not asking whether this is supported currently.
Add a “notes” section like is available in Outlook. In addition, allow sync of these individual notes to Google Drive; perhaps in a folder called “em Client Notes” with each individual note stored as a separate document file in that folder. This is how I manage my notes today so that they are accessible from any web browser; I just don’t have the capability of accessing them from the eM Client application.