Where is iCloud after an upgrade to ios11 I upgraded to ios11 and not only have my iCloud files disappeared - the entire iCloud app is not available.   There were no errors during the installation. 

There are other issues:  there are no "Recent Files" and in the Adobe PDF Viewer the iCloud document that I had been viewing disappeared. (Why was it not stored/copied locally when I was viewing it??)
The iCloud Drive app has been replaced by the Files app in iOS 11. You'll need to open the Files app to refind your files.