In the report type sheet, tick “Attach filled forms as an appendix”: each form selected by the filters is added at the end of the report as a filled-in PDF, exactly as it was entered on site.

Attach filled forms as an appendix option in the report type sheet
The form appendix option.

Without this option, a “Forms” report lists the forms with their fields, without reproducing the PDF. “Include comments” adds the discussion threads.