IronPDF How-Tos Flatten PDFs Flatten PDFs in C# Chaknith Bin Updated:July 28, 2025 PDF documents often include forms featuring interactive fillable widgets, such as radio buttons, checkboxes, text boxes, lists, etc. In order to make it non-editable for different application purposes, we need to flatten the PDF file. IronPDF provides the function to flatten your PDF in C# with just one line of code. Get started with IronPDF Start using IronPDF in your project today with a free trial. First Step: Start for Free How to Flatten PDF Files in C# Install IronPDF from NuGet Package Manager Load existing or create a new PDF from HTML Use the Flatten method to flatten the PDF Save the flattened PDF as a new document Flatten a PDF document in C# with one line of code How to Flatten a C# PDF Install IronPDF software Flatten a PDF file in C# Create unfillable document Flatten C# PDF Document Once the IronPDF package is installed, you can flatten your PDF file with just one line of code. In the code example below, we have selected our PDF using the PdfDocument class. If your project requires it, you can also create a PDF using the ChromePdfRenderer class. To flatten a PDF file, use the Flatten method. This will make the PDF uneditable, removing interactive widgets like radio buttons and checkboxes. Let's see it in action in the flatten PDF C# code example below. :path=/static-assets/pdf/content-code-examples/how-to/pdf-image-flatten-csharp-flatten-pdf.cs using IronPdf; // Select the desired PDF File PdfDocument pdf = PdfDocument.FromFile("before.pdf"); // Flatten the pdf pdf.Flatten(); // Save as a new file pdf.SaveAs("after_flatten.pdf"); Imports IronPdf ' Select the desired PDF File Private pdf As PdfDocument = PdfDocument.FromFile("before.pdf") ' Flatten the pdf pdf.Flatten() ' Save as a new file pdf.SaveAs("after_flatten.pdf") $vbLabelText $csharpLabel Check the Flattened Document In the below output, the first PDF is editable, our original file. Using IronPDF and the code above, we have made it flat or non-editable. You can use this code for any of your .NET PDF project needs. Please noteForms will not be detectable after using the Flatten method. Library Quick Access Read More Documentation Read the Documentation for more on how to flatten PDFs, edit and manipulate them, and more. Visit IronPDF Documentation Ready to see what else you can do? Check out our tutorial page here: Addtional Features Frequently Asked Questions How can I flatten a PDF in C#? You can flatten a PDF in C# by using the IronPDF library. Simply load the PDF with the PdfDocument class, apply the Flatten method, and save the output to create a non-editable document. What steps are involved in making a PDF uneditable using C#? To make a PDF uneditable in C#, first install IronPDF from the NuGet Package Manager. Then load or create a PDF document, apply the Flatten method to remove interactivity, and save the flattened document. Is it possible to flatten interactive elements in any PDF using C#? Yes, using IronPDF, you can flatten any PDF's interactive elements such as forms, checkboxes, and radio buttons, making the document uneditable. How does flattening a PDF help in securing the document? Flattening a PDF secures the document by removing interactive elements, thus preventing any changes or edits to the content, which is ideal for archiving and compliance purposes. Do I need to write a lot of code to flatten a PDF in C#? No, with IronPDF, you can flatten a PDF with just one line of code by applying the Flatten method to your PDF document. Can flattening a PDF be done on newly created PDFs from HTML in C#? Yes, IronPDF allows you to create PDFs from HTML and then flatten them using the Flatten method, ensuring the document is non-editable. What resources are available for learning more about PDF manipulation in C#? You can visit the IronPDF documentation page, which provides extensive guides and API references for manipulating PDFs, including flattening techniques. Chaknith Bin Chat with engineering team now Software Engineer Chaknith works on IronXL and IronBarcode. He has deep expertise in C# and .NET, helping improve the software and support customers. His insights from user interactions contribute to better products, documentation, and overall experience. Ready to Get Started? Free NuGet Download Total downloads: 15,080,714 View Licenses