Explained... Files in iOS 11
Tap Edit and you can add shortcuts to supported storage locations, which also includes third-party services/ software like Dropbox, Transmit and PDF Expert.
Drag folders (but not individual documents) from iCloud Drive to this area, to enable fast access to them. Collapse the menu by tapping the downwards-facing arrow.
3 View types
Drag the files area downwards to gain access to a number of extra settings. Tap the icon towards the top right so you can switch between icon and list views.
4 Sort order
The toolbar defaults to sorting your files and folders by name, but – just as on the Mac – if you prefer you can change this to date, size, or ordering by user-assigned tags.