editing vs written material

editing and written material both are nouns.

Word	Noun	Adjective	Verb	Adverb
editing	Yes	No	No	No
written material	Yes	No	No	No

As nouns, written material is a hypernym of editing; that is, written material is a word with a broader meaning than editing:

editing: putting something (as a literary work or a legislative bill) into acceptable form
written material: the work of a writer; anything expressed in letters of the alphabet (especially when considered from the point of view of style and effect)

Other hypernyms of editing include piece of writing, writing.

editing (noun)	written material (noun)
putting something (as a literary work or a legislative bill) into acceptable form	the work of a writer; anything expressed in letters of the alphabet (especially when considered from the point of view of style and effect)