Anyone can use ChatGPT. You have to create an account to access it though. As for the Bing Chat app I was mistaken that it had been made available to everyone. I thought it had already been made available to everyone. As of now you have to sign up to be put on a waitlist to gain access. I guess I got early access for being a member of the Windows Insider Program.
Here's the link to ChatGPT if you want to create an account and try it out. You don't have to download or install anything. Also it does not have real time data. The model was trained back in 2021 so any current events will not be available.
ChatGPT | OpenAI