The PowerApps and Flow buttons are not currently available from a SharePoint list in the Government Community Cloud. It is available by going to the URL for PowerApps however the app that is created is not dynamically created with the SharePoint list meaning it has a user needs access to both the SharePoint list and the PowerApps app. We have many InfoPath forms that would need to be converted to PowerApps however we can't manage two sets of permissions for this many custom forms. This is needed to push adoption of both PowerApps and Flow in the GCC before InfoPath reaches its end of life.