please explain how to start OAuth web apllication with c#
Please be more specific about your question.
Here are the OAuth docs:
Can you send me sample source code for C# web application
I need to create host through my web application with you selected plans
send invitation link to client(this link should be not visible to client)
hide invention link in video screen.
We do not have an email API, you will need to use a service like SendGrid.
You can do this via our SDKs. Please see the respective SDK reference.
Or you can reach out to support.zoom.us to ask how to do this within the Zoom Client App.