static void DrawFormFields(PdfGraphics graphics)
        {
            // Create a text box field and specify its location on the page.
            PdfGraphicsAcroFormTextBoxField textBox = new PdfGraphicsAcroFormTextBoxField("text box", new RectangleF(30, 10, 200, 30));

            // Specify text box text, and appearance.
            textBox.Text = "Text Box";
            textBox.Appearance.FontSize        = 12;
            textBox.Appearance.BackgroundColor = Color.AliceBlue;

            // Add the text box field to graphics.
            graphics.AddFormField(textBox);

            // Create a radio group field.
            PdfGraphicsAcroFormRadioGroupField radioGroup = new PdfGraphicsAcroFormRadioGroupField("First Group");

            // Add the first radio button to the group and specify its location using a RectangleF object.
            radioGroup.AddButton("button1", new RectangleF(30, 60, 20, 20));

            // Add the second radio button to the group.
            radioGroup.AddButton("button2", new RectangleF(30, 90, 20, 20));

            // Specify radio group selected index, and appearance.
            radioGroup.SelectedIndex = 0;
            radioGroup.Appearance.BorderAppearance = new PdfGraphicsAcroFormBorderAppearance()
            {
                Color = Color.Red, Width = 3
            };

            // Add the radio group field to graphics.
            graphics.AddFormField(radioGroup);
        }
        static void DrawTextBoxField(PdfGraphics graphics)
        {
            // Create a text box field and specify its location on the page using a RectangleF object.
            PdfGraphicsAcroFormTextBoxField textBox = new PdfGraphicsAcroFormTextBoxField("text box", new RectangleF(0, 10, 200, 30));

            // Specify text box properties.
            textBox.Text                       = "Text Box";
            textBox.TextAlignment              = PdfAcroFormStringAlignment.Near;
            textBox.Appearance.FontSize        = 12;
            textBox.Appearance.BackgroundColor = Color.AliceBlue;

            // Add the field to graphics.
            graphics.AddFormField(textBox);
        }