I have Finder set so that iCloud Drive is my New File location. Within iCloud Drive, the majority of my personal files are either under Pages or Numbers because those apps are what I use must to create files. Several days ago I received a letter that I want to be sure to keep and decided the best place not to lose it would be to file it with a file I have within Pages. So I scanned this letter which went to Pictures, then tried to drag-and-drop it into Pages under iCloud Drive. Absolutely no luck; would always bounce back. Tried it with .tiff, then .pdf, then .jpeg. No luck. Finally called Apple, and did a work-around by copying the letter and pasting it into a new Pages sheet. Then exported it directly to iCloud Drive. The Apple Rep said something about iCloud Drive using its own "app" system, and I couldn't drag-and-drop from something outside that hierarchy? Can anyone help me understand this more clearly?