The vast majority of Email clients typically do not support the latest interactive web technologies. Here is a list of the most common asked-about elements that are either not supported or have limited support by most email clients:
Video: Embedded video is not supported by email clients.
<iframe>
Iframes are used embed external content within a document. Most email clients do not support the iframe tag.
<form>
Forms are one of the most common interactive elements on the web, but email clients generally do not support submitting a form on an email.
background-image
Background images are not supported by any email clients.
<style>
background-image: url("background.png");
</style>