iCloud sync

I have been using Dropbox to back up my files, but I've just learned that I can now read Pages files on my phone if they are in iCloud. I've been having to save everything in a Word document format to do that, so this would be much simpler.

I've copied all of my Pages files to iCloud, but I can't find a way to automatically save a copy there when I create new documents or edit those I already have. Is there a way to do this?