Hi,
My apologies as our team is unaware of the Facebook feature that you mentioned as this is already outside of our expertise. Regarding managing accounts using the AdWords API, you can refer to this
guide for more information on what is available and what you can achieve. Basically, once you have linked your accounts to a root MCC, you should be able to manage all it sub-accounts as long as you have the appropriate OAuth2 credentials.
As for integrating the AdWords API to an existing website or third party platform, I'm afraid that our team would not be able to provide further support as this is already out of scope for us. If I may have misunderstood your issue, feel free to write back and provide more context so I can better assist you.
Regards,
Dannison
AdWords API Team