Where can I store documents on the Ipad?

You do not create your own folders for documents. Each Pages document is automatically saved in its own sandbox whenever you create it. That is true for every app that contains data. Whenever you connect to iTunes, all apps and all associated data will be backed up to your computer.

You do have a slight amount of flexibility. For example, pdf documents can be stored in iBooks or in any one a half-dozen pdf reader apps.

I honestly don't know if this topic is covered but you might wish to download the 4.2 User Guide.
http://support.apple.com/manuals/#ipad

A more extensive User Guide is available at no charge from iBooks.

Welcome to Apple Discussions.

The following FAQs might help you

http://support.apple.com/kb/HT4065

As mentioned before you don't need to worry about saving new documents you make with Pages on iPad, they are saved automatically.

It does take a little getting used to not having different folders to organize your stuff in, but they are saved on the device. If you have a mobile me account you could organize files there or iwork.com is free solution to storage.