How to generate fillable PDF form fields using an HTML to PDF converter

The Syncfusion^® HTML-to-PDF converter is a robust .NET library designed to convert HTML, SVG, MHTML, and web pages into high-quality PDF documents using C#. Leveraging the Blink rendering engine (the same engine behind Google Chrome), it delivers precise rendering of text, images, fonts, and layouts.

This article explains how to convert HTML forms into fillable PDF documents using Syncfusion’s .NET PDF library. You’ll learn how to define interactive form fields in HTML, preserve their functionality during conversion, and customize the layout and appearance of the resulting PDF. This approach gives you full control over the form design and ensures a seamless user experience when filling out PDFs.

Steps to generate fillable PDF form fields from HTML using a converter

1. Create a new project: Start a new Console application in .NET Core to facilitate the HTML-to-PDF conversion process.
   
   
2. Install required packages: Add the Syncfusion.HtmlToPdfConverter.Net.Windows NuGet package from Nuget.org.
   
   
3. Set up the environment: In the Program.cs file, include these namespaces.
   C#

using Syncfusion.Drawing;
using Syncfusion.HtmlConverter;
using Syncfusion.Pdf;
using Syncfusion.Pdf.Interactive;
using Syncfusion.Pdf.Parsing;

4. Generate fillable PDF form fields: Follow these steps to convert HTML forms into interactive, fillable PDF documents using an HTML to PDF converter.

C#

// Initialize the HTML to PDF converter
HtmlToPdfConverter htmlConverter = new HtmlToPdfConverter();
// Enable form conversion
BlinkConverterSettings settings = new BlinkConverterSettings
{
   EnableForm = true
};
htmlConverter.ConverterSettings = settings;
// Convert the HTML file to a PDF document
using (PdfDocument document = htmlConverter.Convert(Path.GetFullPath(@"Data/Input.html")))
{
   // Set default appearance for form fields
   document.Form.SetDefaultAppearance(false);

   // Save the PDF document to a memory stream
   using (MemoryStream stream = new MemoryStream())
   {
       // Load the saved PDF document
       document.Save(stream);
       // Load the PDF document containing form fields
       PdfLoadedDocument loadedDocument = new PdfLoadedDocument(stream);
       // Fill the form fields
       PdfLoadedForm form = loadedDocument.Form;
       // Fill the "name" field
       if (form.Fields["name"] is PdfLoadedTextBoxField nameField)
       {
           nameField.Text = "XYZ";
       }
       // Fill the "email" field
       if (form.Fields["email"] is PdfLoadedTextBoxField emailField)
       {
           emailField.Text = "xyz@example.com";
       }
       // Select "Male" in the "gender" dropdown
       if (form.Fields["gender"] is PdfLoadedComboBoxField genderField)
       {
           genderField.SelectedValue = "Male";
       }
       // Fill the "signature" field
       if (form.Fields["signature"] is PdfLoadedTextBoxField signatureTextBox)
       {
           // Get the original field's position and page
           RectangleF bounds = signatureTextBox.Bounds;
           PdfPageBase page = signatureTextBox.Page;
           // Remove the original textbox field
           form.Fields.Remove(signatureTextBox);
           // Create a new signature field at the same location
           PdfSignatureField signatureField = new PdfSignatureField(page, "ClientSignature")
           {
               Bounds = bounds
           };
           // Add the new signature field to the form
           form.Fields.Add(signatureField);
       }
       // Save the PDF document
       loadedDocument.Save(Path.GetFullPath(@"Output/Output.pdf"));
   }
}

A complete working sample can be downloaded from GitHub.

By executing the program, you will generate the following PDF document.

Conclusion
I hope you enjoyed learning how to convert HTML forms into fillable PDF documents using an HTML to PDF converter.

You can refer to our ASP.NET Core PDF feature tour page to know about its other groundbreaking feature representations and documentation, and how to quickly get started for configuration specifications. You can also explore our ASP.NET Core PDF example to understand how to create and manipulate data.
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