How to Convert Word (Docx) to PDF in C# (Tutorial)

Introduction

Converting Word documents to PDF is a common requirement in many business applications, from automating report generation to delivering professional-quality documents. PDFs are universally recognized for their consistent formatting, secure features, and ease of sharing.

In this tutorial, we’ll guide you through the process of converting Word documents (DOCX files) to PDF in C# using the IronPDF library. This step-by-step guide will help you integrate Word-to-PDF functionality into your .NET applications quickly and seamlessly.

Prerequisites

Before starting this tutorial, ensure you have the following:

1. Development Environment

   • A working installation of Visual Studio (2019 or later is recommended).

   • .NET 6.0 or a compatible .NET framework installed.

2. IronPDF Library

   • Install IronPDF via NuGet

   • A valid IronPDF license key

3. A Sample Word Document

   • Prepare a DOCX file (e.g., example.docx) for testing. You can create one using Microsoft Word, Google Docs (exported as DOCX), or any compatible editor.

4. Basic C# Knowledge

   • Familiarity with basic file I/O operations in C#.

Why Convert Word Files to PDF?

Benefits of PDF Over DOCX

PDF is the gold standard for sharing and archiving documents due to its:

• Platform Independence: PDFs look the same regardless of the operating system or device used to open them.

• Data Integrity: Text, images, fonts, and layouts are preserved exactly as intended.

• Security: PDFs support encryption, password protection, and digital signatures, ensuring document confidentiality and authenticity.

Common Scenarios for Word-to-PDF Conversion

Here are some real-world scenarios where Word-to-PDF conversion is essential:

• Contracts and Legal Documents: Generate contracts that preserve formatting and cannot be easily edited.

• Business Reports: Share polished, professional reports with consistent formatting.

• Invoice Generation: Automate invoice creation in a tamper-proof format.

• Document Archiving: Save important Word documents in a long-term, unmodifiable format.

Setting Up the IronPDF Library

To follow along with this tutorial, you’ll need the IronPDF library.

Step 1: Installing IronPDF

IronPDF is available via NuGet. Open your Package Manager Console and run:

Install-Package IronPdf

Install-Package IronPdf

'INSTANT VB TODO TASK: The following line uses invalid syntax:
'Install-Package IronPdf

Alternatively, you can install it via the NuGet Package Manager in Visual Studio. Just go to tools > NuGet Package Manager > Manage NuGet Packages for Solution:

And then search for IronPDF. Here you can install the IronPDF library to your project.

Step 2: Activating Your License

IronPDF offers a free trial, you’ll need to activate a license key for full functionality. To activate, simply add your license key in your code:

IronPdf.License.LicenseKey = "YOUR_LICENSE_KEY_HERE";

IronPdf.License.LicenseKey = "YOUR_LICENSE_KEY_HERE";

IronPdf.License.LicenseKey = "YOUR_LICENSE_KEY_HERE"

Input Word Document

Basic Example Code

The below sample code demonstrates the straightforward process to convert DOCX files to PDF.

using IronPdf;  
using System.IO;  

class Program  
{  
    static void Main(string[] args)  
    {  
        DocxToPdfRenderer renderer = new DocxToPdfRenderer();

    // Convert DOCX to PDF using IronPDF  
    PdfDocument pdf = renderer.RenderDocxAsPdf("newsletter.docx");

    // Save the resulting PDF to a file  
    pdf.SaveAs("output.pdf"); 
    }  
}

using IronPdf;  
using System.IO;  

class Program  
{  
    static void Main(string[] args)  
    {  
        DocxToPdfRenderer renderer = new DocxToPdfRenderer();

    // Convert DOCX to PDF using IronPDF  
    PdfDocument pdf = renderer.RenderDocxAsPdf("newsletter.docx");

    // Save the resulting PDF to a file  
    pdf.SaveAs("output.pdf"); 
    }  
}

Imports IronPdf
Imports System.IO

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		Dim renderer As New DocxToPdfRenderer()

	' Convert DOCX to PDF using IronPDF  
	Dim pdf As PdfDocument = renderer.RenderDocxAsPdf("newsletter.docx")

	' Save the resulting PDF to a file  
	pdf.SaveAs("output.pdf")
	End Sub
End Class

Output PDF Document

Code Explanation

In order to begin converting your DOCX files to PDF, we first need to instantiate the DocxToPdfRenderer. This will handle to conversion of your Word document to PDF format. The next step is to create a new PdfDocument instance that will hold the newly created PDF document, and use the RenderDocxAsPdf method to convert the DOCX file to PDF. Finally, all you need to do is save the PDF document to the desired location using SaveAs and voila! You just converted a DOCX file to PDF in just three easy lines.

Advanced Features for Enhanced PDFs

IronPDF is packed with advanced features to help you customize and enrich your PDF output:

1. Adding Watermarks

Watermarks are useful for branding or marking sensitive documents. You can add watermarks after converting the PDF:

pdf.ApplyWatermark("<h2 style='color:red'>SAMPLE Copy</h2>", 40, IronPdf.Editing.VerticalAlignment.Middle, IronPdf.Editing.HorizontalAlignment.Center);

pdf.ApplyWatermark("<h2 style='color:red'>SAMPLE Copy</h2>", 40, IronPdf.Editing.VerticalAlignment.Middle, IronPdf.Editing.HorizontalAlignment.Center);

pdf.ApplyWatermark("<h2 style='color:red'>SAMPLE Copy</h2>", 40, IronPdf.Editing.VerticalAlignment.Middle, IronPdf.Editing.HorizontalAlignment.Center)

2. Adding Headers to Your PDF

One of the most common customizations for PDFs is adding headers to each page. Headers can include document titles, page numbers, dates, or any other information you wish to display at the top of each page in the PDF.

TextHeaderFooter textHeader = new TextHeaderFooter
{
    CenterText = "Weekly Newsletter!",
};

pdf.AddTextHeaders(textHeader);

TextHeaderFooter textHeader = new TextHeaderFooter
{
    CenterText = "Weekly Newsletter!",
};

pdf.AddTextHeaders(textHeader);

Dim textHeader As New TextHeaderFooter With {.CenterText = "Weekly Newsletter!"}

pdf.AddTextHeaders(textHeader)

3. Customizing PDF Layout

IronPDF allows you to define page settings, such as margins, orientation, and page size, before saving your PDF:

renderer.RenderingOptions.PaperOrientation = PdfPaperOrientation.portrait;

renderer.RenderingOptions.SetCustomPaperSizeinCentimeters(20, 20);

renderer.RenderingOptions.MarginTop = 30;
renderer.RenderingOptions.MarginLeft = 20;
renderer.RenderingOptions.MarginRight = 20;
renderer.RenderingOptions.MarginBottom = 30;

renderer.RenderingOptions.PaperOrientation = PdfPaperOrientation.portrait;

renderer.RenderingOptions.SetCustomPaperSizeinCentimeters(20, 20);

renderer.RenderingOptions.MarginTop = 30;
renderer.RenderingOptions.MarginLeft = 20;
renderer.RenderingOptions.MarginRight = 20;
renderer.RenderingOptions.MarginBottom = 30;

renderer.RenderingOptions.PaperOrientation = PdfPaperOrientation.portrait

renderer.RenderingOptions.SetCustomPaperSizeinCentimeters(20, 20)

renderer.RenderingOptions.MarginTop = 30
renderer.RenderingOptions.MarginLeft = 20
renderer.RenderingOptions.MarginRight = 20
renderer.RenderingOptions.MarginBottom = 30

Full Example Code with Extra Formatting

using IronPdf;
using IronPdf.Rendering;

public class Program
{

    public static void Main(string[] args)
    {
        DocxToPdfRenderer renderer = new DocxToPdfRenderer();

        renderer.RenderingOptions.PaperOrientation = PdfPaperOrientation.Portrait;

        renderer.RenderingOptions.SetCustomPaperSizeinCentimeters(15, 15);

        renderer.RenderingOptions.MarginTop = 15;
        renderer.RenderingOptions.MarginLeft = 20;
        renderer.RenderingOptions.MarginRight = 20;
        renderer.RenderingOptions.MarginBottom = 15;

        // Convert DOCX to PDF using IronPDF  
        PdfDocument pdf = renderer.RenderDocxAsPdf("newsletter.docx");

        pdf.ApplyWatermark("<h2 style='color:red'>SAMPLE Copy</h2>", 40, IronPdf.Editing.VerticalAlignment.Middle, IronPdf.Editing.HorizontalAlignment.Center);

        TextHeaderFooter textHeader = new TextHeaderFooter
        {
            CenterText = "Weekly Newsletter!",
        };

        pdf.AddTextHeaders(textHeader);

        // Save the resulting PDF to a file  
        pdf.SaveAs("output.pdf");
    }
}

using IronPdf;
using IronPdf.Rendering;

public class Program
{

    public static void Main(string[] args)
    {
        DocxToPdfRenderer renderer = new DocxToPdfRenderer();

        renderer.RenderingOptions.PaperOrientation = PdfPaperOrientation.Portrait;

        renderer.RenderingOptions.SetCustomPaperSizeinCentimeters(15, 15);

        renderer.RenderingOptions.MarginTop = 15;
        renderer.RenderingOptions.MarginLeft = 20;
        renderer.RenderingOptions.MarginRight = 20;
        renderer.RenderingOptions.MarginBottom = 15;

        // Convert DOCX to PDF using IronPDF  
        PdfDocument pdf = renderer.RenderDocxAsPdf("newsletter.docx");

        pdf.ApplyWatermark("<h2 style='color:red'>SAMPLE Copy</h2>", 40, IronPdf.Editing.VerticalAlignment.Middle, IronPdf.Editing.HorizontalAlignment.Center);

        TextHeaderFooter textHeader = new TextHeaderFooter
        {
            CenterText = "Weekly Newsletter!",
        };

        pdf.AddTextHeaders(textHeader);

        // Save the resulting PDF to a file  
        pdf.SaveAs("output.pdf");
    }
}

Imports IronPdf
Imports IronPdf.Rendering

Public Class Program

	Public Shared Sub Main(ByVal args() As String)
		Dim renderer As New DocxToPdfRenderer()

		renderer.RenderingOptions.PaperOrientation = PdfPaperOrientation.Portrait

		renderer.RenderingOptions.SetCustomPaperSizeinCentimeters(15, 15)

		renderer.RenderingOptions.MarginTop = 15
		renderer.RenderingOptions.MarginLeft = 20
		renderer.RenderingOptions.MarginRight = 20
		renderer.RenderingOptions.MarginBottom = 15

		' Convert DOCX to PDF using IronPDF  
		Dim pdf As PdfDocument = renderer.RenderDocxAsPdf("newsletter.docx")

		pdf.ApplyWatermark("<h2 style='color:red'>SAMPLE Copy</h2>", 40, IronPdf.Editing.VerticalAlignment.Middle, IronPdf.Editing.HorizontalAlignment.Center)

		Dim textHeader As New TextHeaderFooter With {.CenterText = "Weekly Newsletter!"}

		pdf.AddTextHeaders(textHeader)

		' Save the resulting PDF to a file  
		pdf.SaveAs("output.pdf")
	End Sub
End Class

With this, you can easily convert your DOCX files to a PDF file with custom formatting to fit your needs.

Output PDF Document

Best Practices for Word-to-PDF Conversion

1. Optimize File Sizes

Reduce PDF size by compressing any images within your PDF for faster downloads and smoother sharing:

pdf.CompressImages(40);

pdf.CompressImages(40);

pdf.CompressImages(40)

2. Validate Input Files

Always ensure the DOCX file exists and is valid before processing:

if (!File.Exists(docxPath))  
{  
    throw new FileNotFoundException($"File not found: {docxPath}");  
}

if (!File.Exists(docxPath))  
{  
    throw new FileNotFoundException($"File not found: {docxPath}");  
}

If Not File.Exists(docxPath) Then
	Throw New FileNotFoundException($"File not found: {docxPath}")
End If

3. Secure Your PDFs

Encrypt sensitive documents with a password:

pdf.SecuritySettings.OwnerPassword = "SecurePassword123";
pdf.SecuritySettings.UserPassword = "Password";

pdf.SecuritySettings.OwnerPassword = "SecurePassword123";
pdf.SecuritySettings.UserPassword = "Password";

pdf.SecuritySettings.OwnerPassword = "SecurePassword123"
pdf.SecuritySettings.UserPassword = "Password"

About IronPDF

IronPDF is a powerful .NET library that allows developers to easily create, manipulate, and convert PDF documents. It provides a range of features designed to help you automate and streamline document generation and processing in C# applications. Whether you're converting HTML, DOCX, or image files to PDFs, or editing and extracting text from existing PDFs, IronPDF simplifies these tasks with minimal coding.

Key Features of IronPDF

1. HTML to PDF Conversion:

   • One of the most powerful features of IronPDF is its ability to convert HTML content into PDFs. This makes it perfect for web applications where users need to download reports, invoices, or other documents in PDF format.

   • It supports advanced HTML and CSS, including JavaScript execution, which ensures that the PDF output closely matches the web page design.

2. Image to PDF Conversion:

   • IronPDF can also take images (JPEG, PNG, etc.) and convert them into high-quality PDFs, which is ideal for creating portfolios, photo books, and scanned document archives. Alternatively, IronPDF also supports PDF to image conversion.

3. PDF Editing:

   • You can edit existing PDFs by adding text, images, shapes, annotations, or watermarks. The library also supports merging and splitting PDF files, making it a great tool for document management applications.

4. Form Filling and PDF Generation:

   • IronPDF allows developers to fill form fields in existing PDFs, making it perfect for applications where users need to fill out interactive forms and save them as PDFs.

5. Text Extraction:

   • IronPDF can extract text from PDFs, which can then be used for data analysis, searching, or exporting to other formats (like CSV or Excel). It’s ideal for document processing workflows that need to analyze the content of PDFs.

Conclusion

IronPDF makes converting Word documents to PDF programmatically in C# straightforward, reliable, and feature-rich. With just a few lines of code, you can integrate this functionality into your .NET applications, empowering users to generate professional, high-quality PDFs from DOCX files.

By leveraging IronPDF, developers can streamline workflows for:

• Automating document generation for businesses.

• Ensuring data integrity when sharing files across platforms.

• Creating secure, tamper-proof archives of important Word documents.

Moreover, the advanced features—such as watermarking, merging files, and applying custom layouts—enable you to go beyond basic conversions. These capabilities are ideal for building robust solutions in areas like contract management, invoice generation, and report distribution.

IronPDF stands out with its simplicity, versatility, and developer-friendly API, making it an essential tool for anyone working with document processing in .NET. Try IronPDF out for yourself with its free trial, and see how it can improve your PDF projects today!