You won't solve it without consulting the PDF Reference and some rather low-level and verbose code. If you are lucky, it's indeed PDF Form, i.e. not text as page content, and not XFA form.

Try getFormFieldList method, then getFormField to check them all or access a field with known name. The V entry in field dictionary is its text "value", either in PDFDocEncoding (plain ASCII, for most practical purposes), or UTF16-BE with prepended BOM, as in your example (which is Hebrew).