How to copy and paste the actual video on OS Catalina?

What's wrong with just using the URL? Otherwise, about all you can do in an email is post a small image of what the video is about, followed by the URL, as below.

https://www.youtube.com/watch?v=VIN6TGPC5fk

Still, that depends on both what yours and the recipient's email client support. In MS Outlook, I can paste this picture into an HTML email and assign the URL to it. It would then do pretty much what you want. But then the question becomes, would the email client the recipient is using work with the email I send?

There's a lot of ifs, buts, and maybes when it comes to email.

Copy and paste a video where? Other than that, I've never heard of any way to do such a thing. You'd be trying to copy/paste a multi MB or GB file. You also can't "paste" a video file onto someone else's server or web site. You'd have to upload it, if they provide such an option.

You're welcome. 🙂