I wasn’t sure how to make/embed HTML to create an HTML email newsletter with Apple Mail. But I realized it was rather simple. Please make sure you upload your email newsletter to a webserver, then do the following:

1. Open the page in Safari
   Open the page you uploaded in Safari, then choose File > Mail Contents of This Page. This will load the page into Apple Mail automatically.
2. Enter recipients and send
   Mail will load up and a new email will open that uses the HTML page. Note: the webpage may sometimes look incorrect, but should turn out okay. You should send to yourself first to make sure it displays as you expect.