There are two ways to download the runtime. The "Direct Download" method is best for most users.

Here is the crucial fact you need to know:

.NET 8.0 did not exist in 2021.

If your document, error message, or legacy script explicitly says “2021,” you are likely looking at a typo, or the software actually requires .NET 6.0 (version "60").

The .NET Desktop Runtime allows you to run Windows desktop applications (like WPF and Windows Forms) that were built using .NET 8.0. If you are trying to launch a program and receive an error saying a specific runtime is missing, this is the correct download.