Many of the transform hub items on the transform hub are from third-party transform providers and require an additional API key from the provider in order to use their transforms.

Your Maltego client license comes with access to all the transform in the "PATERVA CTAS" transform hub item and all the other free items on the transform hub. 

To get a API key from a third-party transform providers you will need to contact the provider directly. You will be able to find their contact details on the transform hub.