Adds a free text annotation: text drawn on the page, wrapped inside rect.
public PdfFreeTextAnnotation AddFreeTextAnnotation(PdfRectangle rect, string text, PdfAnnotationOptions? options = null)
The text box in default user space.
The text (Contents); line breaks start new lines.
Font size, text colour, a border colour, flags and markup texts; null for black 12-point text without a border.
ISO 32000-2 §12.5.6.6, Table 177 (DA naming /Helv, PDF 1.3).