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IronPDF Cookbook — Quick Code Examples for C#

#csharp #dotnet

Need a quick IronPDF code example? This cookbook provides copy-paste code snippets for common PDF tasks in C#.

Jump to the example you need:

Table of Contents

  1. HTML to PDF (Basic)
  2. URL to PDF
  3. Add Watermarks
  4. Merge PDFs
  5. Split PDFs
  6. Add Page Numbers
  7. Password Protect
  8. Digital Signatures
  9. Extract Text
  10. Compress PDFs
  11. Convert Images to PDF
  12. Headers and Footers
  13. Custom Margins
  14. PDF/A Archival
  15. Async Batch Processing

1. HTML to PDF (Basic)

Convert HTML string to PDF:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var html = @"
<!DOCTYPE html>
<html>
<head>
    <style>
        body { font-family: Arial, sans-serif; margin: 40px; }
        h1 { color: #333; }
    </style>
</head>
<body>
    <h1>Invoice #12345</h1>
    <p>Date: January 26, 2025</p>
    <p><strong>Total: $1,500</strong></p>
</body>
</html>";

var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("invoice.pdf");
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Convert HTML file to PDF:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlFileAsPdf("invoice-template.html");
pdf.SaveAs("invoice.pdf");
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2. URL to PDF

Render a web page as PDF:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderUrlAsPdf("https://example.com");
pdf.SaveAs("webpage.pdf");
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With custom timeout:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();
renderer.RenderingOptions.Timeout = 120; // 120 seconds

var pdf = renderer.RenderUrlAsPdf("https://example.com");
pdf.SaveAs("webpage.pdf");
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3. Add Watermarks

Add HTML watermark to existing PDF:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("contract.pdf");

pdf.ApplyWatermark(@"
    <h1 style='color: rgba(255,0,0,0.3);
               transform: rotate(-45deg);
               font-size: 60px;'>
        DRAFT
    </h1>");

pdf.SaveAs("contract-draft.pdf");
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Add image watermark:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("document.pdf");

pdf.ApplyWatermark(@"
    <img src='watermark-logo.png'
         style='opacity: 0.5; width: 200px;' />");

pdf.SaveAs("watermarked.pdf");
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4. Merge PDFs

Merge multiple PDFs into one:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf1 = PdfDocument.FromFile("invoice1.pdf");
var pdf2 = PdfDocument.FromFile("invoice2.pdf");
var pdf3 = PdfDocument.FromFile("invoice3.pdf");

var merged = PdfDocument.Merge(pdf1, pdf2, pdf3);
merged.SaveAs("merged-invoices.pdf");
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Merge from file paths:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var files = new[] { "doc1.pdf", "doc2.pdf", "doc3.pdf" };
var pdfs = files.Select(f => PdfDocument.FromFile(f)).ToArray();

var merged = PdfDocument.Merge(pdfs);
merged.SaveAs("merged.pdf");
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5. Split PDFs

Split PDF into individual pages:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("report.pdf");

for (int i = 0; i < pdf.PageCount; i++)
{
    var singlePage = pdf.CopyPage(i);
    singlePage.SaveAs($"page-{i + 1}.pdf");
}
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Extract specific page range:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("report.pdf");

// Extract pages 3-7 (zero-indexed: 2-6)
var excerpt = pdf.CopyPages(2, 6);
excerpt.SaveAs("excerpt.pdf");
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6. Add Page Numbers

Add page numbers to footer:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();

renderer.RenderingOptions.HtmlFooter = new HtmlHeaderFooter
{
    HtmlFragment = @"
        <div style='text-align: center;
                    font-size: 10px;
                    color: #666;'>
            Page {page} of {total-pages}
        </div>"
};

var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("output.pdf");
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Add page numbers with date:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();

renderer.RenderingOptions.HtmlFooter = new HtmlHeaderFooter
{
    HtmlFragment = @"
        <div style='display: flex;
                    justify-content: space-between;
                    font-size: 10px;
                    padding: 0 20px;'>
            <span>{date}</span>
            <span>Page {page} of {total-pages}</span>
        </div>"
};

var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("output.pdf");
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7. Password Protect

Encrypt PDF with password:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("sensitive-data.pdf");

// Owner password (full access)
pdf.Password = "owner-password-123";

// User password (restricted access)
pdf.SecuritySettings.UserPassword = "user-password-456";

// Restrict permissions
pdf.SecuritySettings.AllowUserPrinting = false;
pdf.SecuritySettings.AllowUserCopyPasteContent = false;
pdf.SecuritySettings.AllowUserAnnotations = false;

pdf.SaveAs("encrypted.pdf");
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256-bit AES encryption:

using IronPdf;
using IronPdf.Rendering;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("document.pdf");

pdf.SecuritySettings.OwnerPassword = "owner-pass";
pdf.SecuritySettings.UserPassword = "user-pass";
pdf.SecuritySettings.EncryptionAlgorithm = PdfEncryptionAlgorithm.AES256;

pdf.SaveAs("encrypted-aes256.pdf");
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8. Digital Signatures

Sign PDF with certificate:

using IronPdf;
using IronPdf.Signing;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("contract.pdf");

var signature = new PdfSignature("certificate.pfx", "certificate-password");
signature.SigningContact = "legal@company.com";
signature.SigningLocation = "New York, USA";
signature.SigningReason = "Contract Approval";

pdf.Sign(signature);
pdf.SaveAs("signed-contract.pdf");
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Sign with visible signature image:

using IronPdf;
using IronPdf.Signing;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("contract.pdf");

var signature = new PdfSignature("certificate.pfx", "password");
signature.SignatureImage = "signature-image.png";

pdf.Sign(signature);
pdf.SaveAs("signed-contract.pdf");
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9. Extract Text

Extract all text from PDF:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("document.pdf");
var text = pdf.ExtractAllText();

Console.WriteLine(text);
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Extract text from specific page:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("document.pdf");
var textPage1 = pdf.Pages[0].ExtractText();
var textPage2 = pdf.Pages[1].ExtractText();

Console.WriteLine($"Page 1: {textPage1}");
Console.WriteLine($"Page 2: {textPage2}");
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Search for text:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("document.pdf");
var results = pdf.FindText("invoice");

foreach (var result in results)
{
    Console.WriteLine($"Found on page {result.PageNumber} at position ({result.X}, {result.Y})");
}
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10. Compress PDFs

Compress images in PDF:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("large-report.pdf");

// Compress images to 70% quality
pdf.CompressImages(70);

pdf.SaveAs("compressed-report.pdf");
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Reduce file size with multiple optimizations:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("large-document.pdf");

pdf.CompressImages(75); // JPEG quality
pdf.ReduceFileSize(); // Additional optimizations

pdf.SaveAs("optimized-document.pdf");
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11. Convert Images to PDF

Convert single image to PDF:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = ImageToPdfConverter.ImageToPdf("photo.jpg");
pdf.SaveAs("photo.pdf");
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Convert multiple images to one PDF:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var images = new[] { "page1.jpg", "page2.jpg", "page3.jpg" };
var pdf = ImageToPdfConverter.ImageToPdf(images);

pdf.SaveAs("scanned-document.pdf");
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Convert PDF to images:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("presentation.pdf");
var images = pdf.ToBitmap();

for (int i = 0; i < images.Length; i++)
{
    images[i].SaveAs($"slide-{i + 1}.png");
}
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High-resolution PDF to image:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("document.pdf");
var images = pdf.ToBitmap(dpi: 300); // High DPI for printing

images[0].SaveAs("page1-highres.png");
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12. Headers and Footers

Add header and footer:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();

renderer.RenderingOptions.HtmlHeader = new HtmlHeaderFooter
{
    HtmlFragment = @"
        <div style='text-align: center;
                    font-size: 12px;
                    font-weight: bold;'>
            Company Name
        </div>",
    DrawDividerLine = true
};

renderer.RenderingOptions.HtmlFooter = new HtmlHeaderFooter
{
    HtmlFragment = @"
        <div style='text-align: center;
                    font-size: 10px;'>
            Page {page} of {total-pages}
        </div>",
    DrawDividerLine = true
};

var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("output.pdf");
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Header with logo:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();

renderer.RenderingOptions.HtmlHeader = new HtmlHeaderFooter
{
    HtmlFragment = @"
        <div style='display: flex;
                    justify-content: space-between;
                    align-items: center;'>
            <img src='company-logo.png' height='40'>
            <span style='font-size: 12px;'>Confidential</span>
        </div>"
};

var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("output.pdf");
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13. Custom Margins

Set custom page margins:

using IronPdf;
using IronPdf.Rendering;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();

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

var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("output.pdf");
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Custom page size and orientation:

using IronPdf;
using IronPdf.Rendering;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();

renderer.RenderingOptions.PaperSize = PdfPaperSize.A4;
renderer.RenderingOptions.PaperOrientation = PdfPaperOrientation.Landscape;

renderer.RenderingOptions.MarginTop = 10;
renderer.RenderingOptions.MarginBottom = 10;
renderer.RenderingOptions.MarginLeft = 10;
renderer.RenderingOptions.MarginRight = 10;

var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("landscape.pdf");
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14. PDF/A Archival

Convert to PDF/A (archival standard):

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("report.pdf");

// Convert to PDF/A-2B
pdf.ToPdfA();

pdf.SaveAs("archival-report.pdf");
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Render directly as PDF/A:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();
renderer.RenderingOptions.EnablePdfA = true;

var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("archival-output.pdf");
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15. Async Batch Processing

Async HTML rendering:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();

var pdf = await renderer.RenderHtmlAsPdfAsync("<h1>Async PDF</h1>");
await pdf.SaveAsAsync("output.pdf");
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Batch process multiple invoices:

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var invoices = await _database.GetPendingInvoicesAsync();
var renderer = new ChromePdfRenderer();

foreach (var invoice in invoices)
{
    var html = await RenderInvoiceTemplateAsync(invoice);
    var pdf = await renderer.RenderHtmlAsPdfAsync(html);
    await pdf.SaveAsAsync($"invoices/invoice-{invoice.Id}.pdf");
}
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Parallel batch processing:

using IronPdf;
using System.Threading.Tasks;
// Install via NuGet: Install-Package IronPdf

var invoices = await _database.GetPendingInvoicesAsync();

await Parallel.ForEachAsync(invoices, new ParallelOptions { MaxDegreeOfParallelism = 4 }, async (invoice, ct) =>
{
    var renderer = new ChromePdfRenderer();
    var html = await RenderInvoiceTemplateAsync(invoice);
    var pdf = await renderer.RenderHtmlAsPdfAsync(html);
    await pdf.SaveAsAsync($"invoices/invoice-{invoice.Id}.pdf");
});
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Bonus: Common Patterns

Fill PDF Form Fields 

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("application-form.pdf");

pdf.Form.SetFieldValue("full_name", "John Doe");
pdf.Form.SetFieldValue("email", "john@example.com");
pdf.Form.SetFieldValue("agree_terms", "true");

pdf.SaveAs("completed-application.pdf");
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Extract Images from PDF 

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var pdf = PdfDocument.FromFile("brochure.pdf");
var images = pdf.ExtractAllImages();

for (int i = 0; i < images.Length; i++)
{
    File.WriteAllBytes($"image-{i}.png", images[i]);
}
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Render Razor View to PDF (ASP.NET) 

using IronPdf;
using Microsoft.AspNetCore.Mvc;
// Install via NuGet: Install-Package IronPdf

public async Task<IActionResult> GenerateInvoicePdf(int invoiceId)
{
    var invoice = await _database.GetInvoiceAsync(invoiceId);

    // Render Razor view to HTML string
    var html = await _razorEngine.RenderViewToStringAsync("InvoiceTemplate", invoice);

    // Convert HTML to PDF
    var renderer = new ChromePdfRenderer();
    var pdf = renderer.RenderHtmlAsPdf(html);

    return File(pdf.BinaryData, "application/pdf", $"invoice-{invoiceId}.pdf");
}
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Render JavaScript Charts 

using IronPdf;
// Install via NuGet: Install-Package IronPdf

var renderer = new ChromePdfRenderer();

// Wait for JavaScript to execute
renderer.RenderingOptions.RenderDelay = 1000; // 1 second
renderer.RenderingOptions.EnableJavaScript = true;

var pdf = renderer.RenderHtmlAsPdf(htmlWithChartJs);
pdf.SaveAs("sales-report.pdf");
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Additional Resources

Written by Jacob Mellor, CTO at Iron Software. Jacob created IronPDF and leads a team of 50+ engineers building .NET document processing libraries.

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