Need the right command to send a saved on pc "test.html" file as body message via sendEmail-v156 or similar -- 2

I'm looking for help to find out how to use a locally saved .html template as a body message of an email using software like sendEmail-v156 (link: http://caspian.dotconf.net/menu/Software/SendEmail/) or similar software for use in Windows OS. The reason i want to use this software or similar is because it has the ability to use any email address as a sender to send anonymously. Any help would much appreciated.