A: No, because it is not software. But Windows 10/11 supports it natively via your graphics driver. Update your driver.

To understand why you can’t "download" it, you first have to understand what it is.

To run pixel shaders, you'll need a graphics card that supports shader model 2.0 or higher. Most modern graphic processing units ( Update Pixel Shader :: Hardware and Operating Systems

You immediately searched for a download link, hoping to grab a file that would magically fix your problem. There is no executable file named pixel_shader_2.0_setup.exe . Downloading such a file from untrusted "BEST download" sites is the #1 way to install viruses, adware, or Bitcoin miners on your PC.