Tap the spanner icon in the top right of your screen to open "Tools".
Tap Share and Print.
Tap Open in another document.
Choose a file type to convert your document to.
The document is converted to your chosen format.
Tap Choose App.
Type a name and choose a location within your Dropbox. This document is going to a folder called iPad for educators unless I tap to change.
You can see your document uploading to your Dropbox to be accessible everywhere.
Tap the Share icon for a range of options to share your file.
Tap the Open In icon to send to other apps or print.
And that's how to integrate Dropbox and iWork for iOS.