For HTML2PDF and XML2PDF solution check our PDFDoc Scout ActiveX library instead

using System;
using System.Collections.Generic;
using System.Text;
using Bytescout.PDF;
using System.Diagnostics;

namespace HelloWorld
{
class Program
{
static void Main(string[] args)
{
// Create main PDF Doc Engine
PDFDocEngine engine = new PDFDocEngine("", "");

// Add new document
Document document = engine.AddDocument("InputForm.pdf");

// Append new page to the document
Page page = document.GetPage(0);

// Get control list
ControlList controlList = document.Controls;

// Get indices
uint editBoxNameIndex = controlList.GetIndexByName("editBoxName");
uint editBoxSurnameIndex = controlList.GetIndexByName("editBoxSurname");
uint checkBoxMarried = controlList.GetIndexByName("Married");

// Set values
controlList.SetValueByIndex(editBoxNameIndex, "John");
controlList.SetValueByIndex(editBoxSurnameIndex, "Doe");
controlList.SetValueByIndex(checkBoxMarried, "1");

// Save document
document.Save("FillForm.pdf");

// open generated PDF document in default PDF viewer installed in Windows
Process.Start("FillForm.pdf");
}
}
}

Download example source code: bytescoutpdf_fill_pdf_form_text_and_checkboxes.zip (10 KB)

For HTML2PDF and XML2PDF solution check our PDFDoc Scout ActiveX library instead