legal document vs papers

legal document and papers both are nouns.

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

As nouns, papers is a hypernym of legal document; that is, papers is a word with a broader meaning than legal document:

legal document: (law) a document that states some contractual relationship or grants some right
papers: writing that provides information (especially information of an official nature)

Other hypernyms of legal document include document, written document.

legal document (noun)	papers (noun)
(law) a document that states some contractual relationship or grants some right	writing that provides information (especially information of an official nature)