Apple has released iOS 18.2, iPadOS 18.2, and macOS Sequoia 15.2 updates, introducing ChatGPT integration for Apple Intelligence. This feature allows users to access OpenAI's platform without needing a premium account or standalone app. With the service enabled, Siri can ask users to approve accessing ChatGPT for certain questions. The new Writing Tools feature also includes Compose, which enables users to write content based on prompts.

Source: https://techcrunch.com/2024/10/23/heres-how-chatgpt-integration-works-for-apple-intelligence/