work permit vs work papers

work permit and work papers both are nouns.

Word	Noun	Adjective	Verb	Adverb
work permit	Yes	No	No	No
work papers	Yes	No	No	No

As nouns, work permit and work papers are synonyms defined as:

work permit and work papers: a legal document giving information required for employment of certain people in certain countries

Other synonyms of work permit include working papers.

work permit (noun)	work papers (noun)
a legal document giving information required for employment of certain people in certain countries	a legal document giving information required for employment of certain people in certain countries