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 What is PDF flattening? PDF flattening is the process of converting interactive PDF elements, such as forms and annotations, into a static format that makes the document uneditable. Why would you need to make a PDF uneditable in C#? Flattening a PDF in C# is useful for creating uneditable documents, ensuring the contents cannot be altered, which is beneficial for archiving, compliance, and secure document distribution. How can a library help in flattening PDFs? IronPDF provides a straightforward method to flatten PDFs using C# code. You can use its library to convert interactive PDFs into flat, non-editable documents with a single line of code. What is the basic code to flatten a PDF using a library? To flatten a PDF using IronPDF, you load the PDF using the PdfDocument class, call the Flatten method, and save the flattened PDF. This process removes all interactive elements from the document. What are the steps to make a PDF document uneditable in C#? The steps include installing IronPDF from the NuGet Package Manager, loading an existing or creating a new PDF, using the Flatten method, and saving the flattened PDF as a new document. Can a library flatten any PDF document? Yes, IronPDF can flatten any PDF document, making it non-editable by removing interactive elements like forms, checkboxes, and radio buttons. Do I need any specific software to flatten PDFs? You need to install the IronPDF software, which can be added to your project via the NuGet Package Manager, to use its functionalities including PDF flattening. Where can I find more documentation on using a PDF library? You can read more documentation on IronPDF's official website, which provides comprehensive guides and API references for using the library to manipulate PDFs. 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: 14,631,247 View Licenses