If you have an ancient MSDN subscription that includes Visual Studio 6.0 (unlikely for new subscribers), you can download the ISO from the legacy subscriber portal.
Microsoft still hosts Visual FoxPro 6.0 on its website, but it's not easily accessible. You need to search for the software in Microsoft's download center: Microsoft Visual Foxpro 6.0 Download
However, here are the most practical options to obtain it: If you have an ancient MSDN subscription that