Where to buy HBAR in the USA?

I'm curious about the process of purchasing HBAR, a cryptocurrency, in the USA. Could you please elaborate on the various platforms or exchanges that offer this service? Are there any specific requirements or steps I need to follow to successfully buy HBAR in the United States? Also, is there a recommended exchange based on security, ease of use, and transaction fees? I'd appreciate any insights or tips you could provide to help guide me through this process. Thank you for your assistance.