I've got a Wordpress website that exposes APIs to obtain content. I have the admin console but I'm not sure how to locate the interface / documentation. How do you do this? Any pointers is going to be greatly appreciated. Thanks.

You will want to open Wordpress-ADMIN with the addition of /wordpress-admin towards the finish of the WordPress installation's URL and when you are there expand the Configurations Panel > Click Writing and scroll lower towards the section labeled Remote Posting and note the Atom Posting Protocol and XML-RPC.

For more information please visit the WordPress Codex documentation on Settings Writing Screen.