Are you sure it's in your email? A video in an email would be HUGE. Most of the time, video links are sent through emails, and when you click on it, you go to the website that has the video uploaded to it. If that's the case, then all you have to do is provide the link, or address to the site so others can link to it.
If it was actually in the email, then you have to download it to your computer and then upload it to a site that shares videos, like youtube, and provide a link.
Eddie