A false document is a literary technique employed to create verisimilitude in a work of fiction. By inventing and inserting documents that appear to be factual, an author tries to create a sense of authenticity beyond the normal and expected suspension of disbelief for a work of art. The goal of a false document is to convince an audience that what is being presented is factual.
False documents intentionally blur the boundaries between fiction and fact, and, in some cases, the difference between an artistic achievement and a convincing forgery is slight.
A false document is usually created as an artistic exercise, but occasionally is promoted in conjunction with a criminal enterprise, such as fraud, forgery, or a confidence game.
It has been argued that the Voynich Manuscript is possibly a false document - for example it could have been used by alchemists and others to support their presentation.
More information, and a list of examples, on the current version of Wikipedia page [1], with the category Document forgeries at [2] - and also False documentation [3].
There are a number of webpages on 'false documents' in the legal sense.
See also False writing system