RenderBody:
RenderBody method exists in the Layout page to render child page/view. It is just like the ContentPlaceHolder in master page. A layout page can have only one RenderBody method.
@RenderBody()
RenderPage:
RenderPage method also exists in the Layout page to render other page exists in your application. A layout page can have multiple RenderPage method.
@RenderPage("~/Views/Shared/_Header.cshtml")
