What documents can one create using word processing as an application software?

The answer to this question is "Text documents".

Explanation:

A word processing software is application software that provides a facility to write, store, and modify documents and display them on a computer screen and this software also provides a facility to print a document.

Some of these software are freely available on the internet, that is used for word processing, which are Word Star, Word Perfect, Etherpad, Google Docs, etc. In word processing software we only use the text documents.