By default, all the required libraries for build ASP.NET applications are included during the installation of Visual Studio. If a newer version of ASP.NET is released that was not included with Visual Studio, you can download the appropriate SDK library from Microsoft, which will include all the necessary libraries for that version.
Similarly, the Windows operating system comes pre-installed with a more recent version of ASP.NET and is automatically registered with IIS for configuration and execution. Similarly, if a newer version of ASP.NET becomes available, you can install the SDK for the version you need and then use the
aspnet_regiis tool to register the framework with IIS for use.
It should be also noted that for server deployments, there also exists a ASP.NET SDK Redistributable package. This version is a streamlined version of the SDK, with just the essential libraries and does not have the tools and integrations with Visual Studio in it.