written document vs papers

written document and papers both are nouns.

Word	Noun	Adjective	Verb	Adverb
written document	Yes	No	No	No
papers	Yes	No	No	No

As nouns, written document and papers are synonyms defined as:

written document and papers: writing that provides information (especially information of an official nature)

Other synonyms of written document include document.

written document (noun)	papers (noun)
writing that provides information (especially information of an official nature)	writing that provides information (especially information of an official nature)