Apple has removed Apps from the iTunes Store, so manually dragging any desktop file to via iTunes to sync is now obsolete. I prefer not to use DropBox. With the recent iOS 11 upgrade, users are now forced to manage apps strictly on the iOS device. I tried dragging the file from iCloud, but you cannot open the file from the iOS device. It attempts to open the Scrivener app, but you will get an error message.
Temporary Fix Found: I was able to actually resolve this. You have to make a copy of the file uploaded to the iCloud drive. Then, once copied, it appears to copy and save in the format needed for the iOS device. Once you click to open the mobile file, the Scrivener application will open. I don’t mind doing this, but someone will as it takes time away.