How to use PHP POST METHOD

Hi all,
Anyone can tell me how to use the PHP POST method to send the form data to a URL?

I am not asking about creating a new wordpress post, I am not interested in that, I need to send the data to a custom external URL when the form is submitted.

Can anyone tell me how to define the custom external URL to send the data to?

Can anyone tell me how to pass the data?

Thank you