Reply Tool topics in the docs:
GcPdfViewer enhances your PDF form filling experience by allowing you to:
The PDF form field values, when filled in Form Filler dialog are reflected in the underlying PDF form. You can also save the filled form on client by using SupportApi. Use FormFillerSettings and FormFieldMapping settings to control the appearance, behavior and validation settings for the input field inside the Form Filler dialog.
GcDocs PDF Viewer supports Document List Panel, which can be filled with a customized list of PDF documents that you can open by selecting from the list. The list of available documents is specified by the documentListUrl viewer option.