I am not sure I follow. You can find endpoints for individual services at
https://developers.google.com/adwords/api/docs/reference/ (lookup the documentation for each service). AdWords API is a SOAP API. SOAP uses XML as the payload format and HTTPS as the transport protocol. So yes, you can make an API call using HTTPs alone, but you sill need to know XML and SOAP protocol to be able to make a successful call. Here's an
example for making raw HTTP calls.
Hope this helps? Let me know if you have more questions.