How to make closed webinars on the site?

Question

YouTube

Good afternoon!
Tell me how you can organize closed webinars on your website?
You also need the ability to save the video after the end of the webinar and the presence of an online chat.
The first thing I thought about was Youtube. On the site, we can close the page. But is it possible to do it on Youtube itself?
If you make a Youtube channel private, will it be possible to watch videos on the site?
Or maybe there is some other suitable service?