OpenAI has introduced a new feature that integrates ChatGPT directly into Microsoft Word through a sidebar extension. This allows users to summarize text, rephrase sentences, correct spelling, and reformat document titles while working on open files. The extension, called "ChatGPT for Microsoft Word," builds on similar tools already available for Excel and PowerPoint. It is accessible across all Microsoft Word plans, including free, Business, and Enterprise versions. Beginning October 1, 2026, the feature will be enabled by default in enterprise environments, though administrators can choose to disable it if needed. For users on the Free and Go plans, ChatGPT in Word uses the GPT-5.6 Luna model, which is described as the fastest but least powerful in the series. The more advanced GPT-5.6 Sol model, which offers better performance, is available to Business and Enterprise users. OpenAI is offering free access to the Sol model for these users from September 17 to September 30, without impacting their regular usage limits. This temporary free access aims to let users become familiar with the tool before charging for its use, with costs based on the number of "tokens" processed—essentially, the amount of text processed by the AI. OpenAI is not the first to bring an AI assistant into Microsoft Office. Earlier in 2026, Anthropic introduced its AI, Claude, into Excel and PowerPoint, and later into Word in April of the same year. Meanwhile, ChatGPT has also expanded its reach beyond the office suite by adding support for Chrome extensions, enabling users to install tools like the password manager 1Password directly in their browsers. These updates help ChatGPT gain more presence in both productivity software and the broader web browsing experience. In addition to the ChatGPT integration, two other updates were introduced. Multi-account management, which was previously limited to Google services like Gmail and Calendar, is now available across most modules, allowing users to connect both personal and professional accounts of the same service in a single conversation. Another new feature, called Appshots, is coming to Windows. For Word users, ChatGPT directly competes with Microsoft's own Copilot feature, which is not free on all plans. The ChatGPT extension can be installed from the Office modules store, specifically for the desktop version of Word.