Can anyone give me an example to use authentication and authotization in MVC and C#?

The ASP.NET MVC site has plenty of documentation on authentication and authorisation.

You can choose to ASP.NET Forms Authentication in your ASP.NET MVC application. Also, in MVC 5 (based on .NET 4.5) there is no seperate MVC components (installer); everything is one single Web application and working with web forms and MVC is more seamless.

http://www.asp.net/mvc/overview/security