Lots of ways to skin that cat.
You can email it to yourself from a desktop. Find it in a browser on PC, copy and paste the link to an email to yourself. Then copy/paste that link on the smartphone to more people via text or email.
You can find the same video through your smartphone's web browser. Every one I have used offers a way to copy/share the web address and paste into email or text.
Install the Youtube app on the smartphone. Find the video. "Share".