When composing a document or preparing a message, there are many different ways to express that something has been established or recorded in writing. One might use the phrase "in black and white" to indicate that a piece of information has been put down on paper, or perhaps "inscribed" to suggest that something has been permanently engraved or etched. "Documented" and "recorded" are also useful synonyms for "in writing," as they both suggest that information has been captured and preserved for future reference. Other options include "penned," "jotted down," and "scribbled," all of which can be useful depending on the tone and context of the writing in question.