If your girlfriend (fiancée?) intends to spend more than 30 days in the US, look up the new requirement to register with USCIS.
Otherwise, if you look at the history of your posts, you will find answers that are still valid.
Final note, please, please, do not trust ChatGPT or other AI. Especially not for anything important. Ok to generate an overview, but go to the source (CBP, USCIS,IRS, etc.) and double triple check what is actually the accurate information in your situation.
The guides here on VJ are also a good start on all the steps you will have to complete (again, do not trust blindly and go back to the actual form instructions).