The Ghostwriter OpenAI ChatGPT is a writing assistant that has been introduced for Microsoft Office. It is a revolutionary tool that assists in quickly and accurately putting down ideas on paper. The add-in is equipped with advanced natural language processing and machine learning technology, which enables the user to brainstorm, plan, and create content at an unprecedented pace. Ghostwriter is available for Excel, PowerPoint and Word in this add-in. It works on Windows, Mac, Web and iPad. Ghostwriter for Outlook is available in a separate add-in available on Windows, Mac and Web.