Email is a great way to promote resources, and videos are now among the best resources most of us have got. However, it’s not a good idea to embed videos in emails, because many email apps won’t support them, and I suspect some services would push the emails towards spam traps. As this excellent article suggests, the best approach is to send an image of the video with a ‘Play’ button, so that when recipients click it, they’re sent to a web page with the video. Adding a play button to a still frame from the video is pretty straightforward in an image editor, but there’s even an online resource to do just that. As a final touch, rather than send people to a YouTube page, you could send them to a page that contains the full screen video and nothing else, with the video set to autoplay.