The Admin will also have the option to enable "reCAPTCHA" from the Permissions page. Once this setting is enabled, the Admin will then need to sign up for an API key pair for their site by visiting http://www.google.com/recaptcha/admin.
The key pair consists of a site key and secret key. The site key is used to invoke the reCAPTCHA service on the portal. The secret key authorizes communication between your application backend and the reCAPTCHA server to verify the user's response. The secret key needs to be kept safe for security purposes. First, the Admin will choose the type of reCAPTCHA and then fill in authorized domains or package names. After accepting the terms of service, the Admin will get the API key pair.
Please make sure to keep the "Secret Key" saved in a safe place such as a password manager. The "Site Key" and "Secret Key" can now be copied in the WordPress plugin to complete the reCAPTCHA configuration.