What information is sent to OpenAI?

If you are using the AI features like transcription or "Prompt AI" using the command bar some data is sent to OpenAI for processing. If you are using "Prompt AI" through the command bar or on iOS using the toolbar "Prompt AI on selection", only the selected text and your prompt are uploaded to OpenAI to generate an answer. If you are transcribing your voice, only the recorded audio file is uploaded for processing.

Nothing else is shared with OpenAI. Your existing notes, or the content of the currently opened note (except the selected text if you are using the AI features), stay private (still synced via Apple's CloudKit / iCloud Drive, if you didn't opt out).

This makes the AI features by default "opt-out". By using them you opt-in sending a very limited amount of information.