Apple Mail Font Issues with Outlook:
Have you noticed that your emails send from Apple Mail arrive in Outlook most likely in Times Roman and not displaying the font you think you set in Apple Mail?
There are several work arounds. One is to add some empty lines in the signature and start typing there when writing an email. Another is to select all body text before sending the email out and manually setting the font to something like Arial to be sure the receiver using Outlook sees the email’s body text in Arial. This is all cumbersome.
After some research I came across this “Universal Mailer” plugin for Apple Mail: “Usage is straightforward: enable the plugin, set a default font for outgoing emails and you’re done: the next email you’ll send will have a nice default font.”