UseChatGPT.AI is a free Chrome extension that allows users to access ChatGPT and GPT-4 AI models on any website. Users can write, rephrase, summarize, translate, explain, or reply to any text on any website without copy-pasting. Users can also chat with the AI models to ask further questions or refine the results. UseChatGPT.AI works on any language and supports GPT-4. Users need to have a ChatGPT account and pass the Cloudflare check to use the extension.