A copy of the Java API documentation is installed under the API folder in your Kofax RPA installation folder, for example C:\Program Files\Kofax RPA 10.4.0\API. Open the Overview.html file from the API folder and browse for the topic you are interested in.

You can also read the Developer's Guide that contains information about programming for Kofax RPA. The guide can be accessed in the Kofax RPA > Documentation on the Start menu.