The new data add-on functionality is available only when used with the FullContact Enrich Person or FullContact Company APIs.
In addition to add-ons, Enrich APIs also provide a better security using OAuth authentication.
How to Use Enrich Person or Enrich Company APIs:
1) Login to dashboard
2) Generate new API key(s) & copy them to clipboard (API keys are obfuscated and cannot be retrieved once the popup goes away)
3) Use the new API key to authenticate as explained here.
4) Check-out our API documentation here for more information.
If the access to the account or the email address is not possible, please refer to the instructions on changing access on your account. You can find that information here.