Gives the document an interactive form with no fields and default resources, and returns it.
public PdfAcroForm CreateAcroForm()
Add methods, such as AddTextField(String, PdfPage, PdfRectangle, PdfFieldOptions?).ISO 32000-2 §7.7.2, Table 29 (AcroForm, PDF 1.2), and §12.7.3, Table 224: a new indirect dictionary with an empty
Fields, default resources (DR) whose fonts are Helvetica in WinAnsiEncoding as Helv and ZapfDingbats as
ZaDb (standard 14 fonts, §9.6.2.2), and the default appearance /Helv 0 Tf 0 g (auto-sized black text,
§12.7.4.3). It has no NeedAppearances: every field created through it gets its appearances. A mutation: no read may
run concurrently with it.