I am Application Repackager, could anyone know steps to customize an MSIX installer. Same as we add MSTs to Vendor MSIs if any changes require.
How can we add/modify an MSIX file using Adminstudio?
Take a look at the MSIX Packaging Tool from the Store:
For AdminStudio ask Flexera when they plan to support MSIX.
Here is a info from Flexera to MSIX: