The correct answer to this open question is the following.
Vanessa is a research analyst. Before starting a major section of a project related to problem-solving, Vanessa types out a one-page report that summarizes the issue, major information about it, her group's plan, and her group’s rationale for doing what it plans to do. She prints the document and gives it to her boss. Given this information, this document is called a written brief.
A good writing brief summarizes the content of the project or the research. Before you elaborate one, have a clear idea of the most important elements to be included and can be relevant for the reader. It contains the what, the why, and the how. This is the necessary information that will help understand the decision-maker the nature of the project.