While creating an e-mail via IBM iNotes using a Google Chrome browser, selecting the different fonts in the HTML editor (ie Monospace, Arial, and Georgia) has no effect on the way the text is rendered.
The cause of this issue has been determined to be an issue with Google Chrome and has been reported to Google.
Bug Report: https://bugs.webkit.org/show_bug.cgi?id=93491
Additional information available here.
Resolving the problem
As this is an issue with the Google Chrome browser, the permanent resolution is to wait for the fix to be rolled into a released version of Google Chrome. Users can use another web browser as a workaround.