Document Automation - Create a Learning Instance to Extract File Name

Newer bot builder here, and I just created a Learning Instance in Document Automation where I can extract First Name, Last Name and Case Number for a document. An output file is created successfully for each file I process. I cannot figure out how to extract the PDF file name into the same output file. Is there a way to do this? I need the file name to be extracted into the same output file so the next step in the process it can match up the proper file with the first name and last name to docket the correct file with it in the case management system.