Embedding Videos in Email Newsletters
You can't embed a video directly in an email. Most email clients don't support the code required to play the video. Therefore, what most people do is make a screen shot of the video and link it to a page on their website where the video will automatically play.
We recommend creating a YouTube account if you don't already have one, to upload videos and embed them on a page of your website.
How to Make YouTube Videos Play Automatically
To autoplay a YouTube video that has been embedded on your website, just add the autoplay parameter to the embed code's "src" attribute immediately following the video ID, as shown in the following example. The autoplay parameter is: autoplay=1.
<iframe width="560" height="315" src="https://www.youtube.com/embed/t7-3GCXsguo?autoplay=1" frameborder="0" allowfullscreen></iframe>
Note that the first parameter you add after the video ID should start with a question mark, and any subsequent parameters should be separated by an ampersand (&). For example, if you use the parameter that hides related videos that normally appear after the embedded video is finished playing (rel=0), the embed code should look like this:
<iframe width="560" height="315" src="https://www.youtube.com/embed/t7-3GCXsguo?rel=0&autoplay=1" frameborder="0" allowfullscreen></iframe>