Official FOD ISOs are typically reserved for enterprise and development environments rather than general consumer download pages.
Because 21H2 is out of support, Microsoft has removed many direct download links for its supplementary media (including FOD ISOs) from public-facing sites. If you search Google and land on a third-party site offering “Windows 10 21H2 FOD ISO download”: windows 10 21h2 features on demand iso download best
Mount it or extract contents.
Features on Demand (FODs) are optional Windows feature packages that can be added at any time. While Windows typically fetches these from Windows Update when needed, the allows you to preinstall them or add them in environments without internet access. Features On Demand | Microsoft Learn Official FOD ISOs are typically reserved for enterprise
For those without VLSC access, the Windows Assessment and Deployment Kit (ADK) for Windows 10 21H2 includes a subset of these features, though the full ISO remains behind a licensing wall. Features on Demand (FODs) are optional Windows feature
While not a direct FOD ISO, the includes many FODs needed for deployment. Download from Microsoft’s documentation site.