Using C# PDF SDK
C# PDF Builder: How to add form fields to PDF file
C# Demo Code to add a form fields to adobe pdf file
Add text box form field
String outputFilePath = Program.RootPath + "\\" + "Sample91.pdf";
Document document = new Document();
PDFBuildHandler.Create(document, outputFilePath);
document.Open();
document.Add(new Paragraph("This is a sample for Text Form Field:"));
document.Add(new Paragraph(" "));
// create a Text Box form field
FormFieldTextBox textBox = new FormFieldTextBox("TextBox1");
textBox.Text = " ";
textBox.Width = 400;
textBox.Height = 100;
// add form field
document.Add(textBox);
document.Close();
Add check box form field
String outputFilePath = Program.RootPath + "\\" + "Sample92.pdf";
Document document = new Document();
PDFBuildHandler.Create(document, outputFilePath);
document.Open();
document.Add(new Paragraph("This is a sample for Text Form Field:"));
document.Add(new Paragraph(" "));
// create a Text Box form field
FormFieldCheckBox checkbox = new FormFieldCheckBox("CheckBox1");
checkbox.Text = " ";
checkbox.Width = 50;
checkbox.Height = 50;
// add form field
document.Add(checkbox);
document.Close();