atryan wrote:
For example, if I buy an API key of ChatGPT, will I be able to use it on scratch?

Well first this topic probably belongs in the “Advanced Topics” topic. Second I really don't know much about API keys but pretty sure it's just a key to the API of (for example) ChatGPT. Meaning yes, you can get the code of it but you can't port it into scratch as scratch uses it's own special coding language.