All files in iOS are sandboxed; in other words they live within the folder structure of a single app. This is also true for files accessed via the Alfresco app.
Apple have attempted to address the "edit document" case in iOS 8 and newer through something called the "Document Provider" which is part of iCloud Drive. The way this works is that you access Alfresco document from the third party app you wish to use as an editor, for example Microsoft Word.
In Microsoft Word, choose "Open", then "More", tap "Locations". If Alfresco is not in the list, choose "More" and enable Alfresco via the toggle switch. Alfresco will then be available as a file source. When you open Word documents this way, Word saves them back directly to Alfresco.
At least that's the theory. In practice we've found the sequence somewhat prone to issues - not just when using Word & Alfresco, but other third party apps. So just be aware you may need to check your changes have saved correctly. We're working with Apple (as I'm sure are other vendors) to make this system more robust.
Thanks,
Mike