https://arstechnica.com/information-technology/2023/07/pocket-assistant-chatgpt-comes-to-android/

On Tuesday, OpenAI released an official ChatGPT app for Android, now available in the Google Play store in four countries: the US, India, Bangladesh, and Brazil, with more coming soon. As a client for OpenAI's language model family, the GPT-3.5 and GPT-4 models run on the cloud and provide results to your Android device. It also integrates OpenAI's Whisper model for speech recognition.