to remove, obscure, or otherwise censor portions of the text in a document before it is released or published, usually for security or legal reasons;
e.g. He used a thick black marker to redact the confidential details from the document.
(verb)
to edit a document in preparation for publication or release, especially by adapting the information presented or selecting the information to be presented;
e.g. She intended to redact most of the document and reduce it to a page containing just the essential details.