How to get OpenAI API key?

Can you please provide a step-by-step guide on how to acquire an OpenAI API key? I'm new to this and would appreciate clear instructions. Is there a specific registration process I need to follow? Do I need to provide any personal information or documentation? Also, are there any fees associated with obtaining and using the API key? I'm eager to start experimenting with OpenAI's capabilities, so any help you can offer would be greatly appreciated.