IronPDF How-Tos Add and Edit Annotations How to Add and Edit PDF Annotations Chaknith Bin Updated:July 28, 2025 Your business is spending too much on yearly subscriptions for PDF security and compliance. Consider IronSecureDoc, which provides solutions for managing SaaS services like digital signing, redaction, encryption, and protection, all for one-time payment. Explore IronSecureDoc Documentation Annotations allow users to add comments, reminders, or additional information to specific sections of the document. They enhance collaboration and communication in working with PDFs, enabling users to annotate, comment on, and provide context for shared content. Get started with IronPDF! Start using IronPDF in your project today with a free trial. First Step: Start for Free How to Add and Edit PDF Annotations Download the C# Library for PDF Annotations Load an existing or render a new PDF document Use the Add Method to Add Annotations Retrieve and Edit PDF Annotations Remove Annotations from PDF Documents Add Annotations Example PDF annotations allow the addition of "sticky note"-like comments to PDF pages. By using the Add method of the Annotations property, annotations can be programmatically added. TipsAll page indexes follow zero-based indexing. :path=/static-assets/pdf/content-code-examples/how-to/annotation-add-annotation.cs using IronPdf; using IronPdf.Annotations; ChromePdfRenderer renderer = new ChromePdfRenderer(); PdfDocument pdf = renderer.RenderHtmlAsPdf("<h1>Annotation</h1>"); // Create a PDF annotation object on a specified page index TextAnnotation annotation = new TextAnnotation(0) { Title = "This is the title", Contents = "This is the long 'sticky note' comment content...", X = 50, Y = 700, }; // Add the annotation pdf.Annotations.Add(annotation); pdf.SaveAs("annotation.pdf"); IRON VB CONVERTER ERROR developers@ironsoftware.com $vbLabelText $csharpLabel PDF with an Annotation The annotation in the PDF document above can be viewed with the Chrome browser. Retrieve and Edit Annotations Example Retrieving and editing PDF annotations improves collaboration by enhancing clarity, accuracy, and usability. Access the annotation collection through the Annotations property and update properties such as Title, Contents, X, Y, and more with new information. :path=/static-assets/pdf/content-code-examples/how-to/annotation-edit-annotation.cs using IronPdf; using IronPdf.Annotations; using System.Linq; PdfDocument pdf = PdfDocument.FromFile("annotation.pdf"); // Retrieve annotation collection PdfAnnotationCollection annotationCollection = pdf.Annotations; // Select the first annotation TextAnnotation annotation = (TextAnnotation)annotationCollection.First(); // Edit annotation annotation.Title = "New title"; annotation.Contents = "New content..."; annotation.X = 150; annotation.Y = 800; pdf.SaveAs("editedAnnotation.pdf"); Imports IronPdf Imports IronPdf.Annotations Imports System.Linq Private pdf As PdfDocument = PdfDocument.FromFile("annotation.pdf") ' Retrieve annotation collection Private annotationCollection As PdfAnnotationCollection = pdf.Annotations ' Select the first annotation Private annotation As TextAnnotation = CType(annotationCollection.First(), TextAnnotation) ' Edit annotation annotation.Title = "New title" annotation.Contents = "New content..." annotation.X = 150 annotation.Y = 800 pdf.SaveAs("editedAnnotation.pdf") $vbLabelText $csharpLabel PDF with an Edited Annotation The annotation in the PDF document above can be viewed with the Chrome browser. Remove Annotation Example Easily remove unnecessary or outdated annotations using the following methods: RemoveAt, RemoveAllAnnotationsForPage, and Clear. RemoveAt: Remove a single annotation with a specified index. RemoveAllAnnotationsForPage: Remove all annotations on a specified page. Clear: Remove all annotations in the document. Remove a Single Annotation To remove a single annotation, use the RemoveAt method with the corresponding index based on the annotation collection index. :path=/static-assets/pdf/content-code-examples/how-to/annotation-remove-single-annotation.cs using IronPdf; PdfDocument pdf = PdfDocument.FromFile("multipleAnnotation.pdf"); // Remove a single annotation with specified index pdf.Annotations.RemoveAt(1); pdf.SaveAs("removeSingleAnnotation.pdf"); Imports IronPdf Private pdf As PdfDocument = PdfDocument.FromFile("multipleAnnotation.pdf") ' Remove a single annotation with specified index pdf.Annotations.RemoveAt(1) pdf.SaveAs("removeSingleAnnotation.pdf") $vbLabelText $csharpLabel Removed a Single Annotation on PDF Before After The annotation in the PDF document above can be viewed with the Chrome browser. Remove All Annotations To remove all annotations on a particular page, use the RemoveAllAnnotationsForPage method and specify the page index. If you want to remove all annotations in the entire document, simply call the Clear method on the Annotations property. :path=/static-assets/pdf/content-code-examples/how-to/annotation-remove-all-annotation.cs using IronPdf; PdfDocument pdf = PdfDocument.FromFile("multipleAnnotation.pdf"); // Remove all annotaions on a specified page pdf.Annotations.RemoveAllAnnotationsForPage(0); // Remove all annotaions on the document pdf.Annotations.Clear(); pdf.SaveAs("removeAllAnnotation.pdf"); Imports IronPdf Private pdf As PdfDocument = PdfDocument.FromFile("multipleAnnotation.pdf") ' Remove all annotaions on a specified page pdf.Annotations.RemoveAllAnnotationsForPage(0) ' Remove all annotaions on the document pdf.Annotations.Clear() pdf.SaveAs("removeAllAnnotation.pdf") $vbLabelText $csharpLabel Ready to see what else you can do? Check out our tutorial page here: Edit PDFs Frequently Asked Questions How can I add annotations to a PDF in C#? You can add annotations to a PDF in C# by using IronPDF. First, download the C# library for PDF annotations. Load an existing or create a new PDF document, then use the Add method of the Annotations property to insert comments or notes. How do I edit existing annotations in a PDF using C#? To edit existing annotations in a PDF using C#, access the annotation collection through IronPDF's Annotations property. Update properties such as Title, Contents, X, and Y with new information to modify the annotations. What is the process for removing annotations from a PDF using C#? You can remove annotations from a PDF using IronPDF by employing methods like RemoveAt to delete a specific annotation, RemoveAllAnnotationsForPage to clear all annotations on a page, or Clear to remove all annotations from the document. Can I view PDF annotations in a web browser? Yes, annotations added to PDF documents using IronPDF can be viewed in web browsers such as Chrome. What are the benefits of adding annotations to PDF documents? Adding annotations to PDF documents with IronPDF enhances collaboration by allowing users to add comments, reminders, or additional information, improving communication and context for shared content. How can I find documentation for digital signing and encryption services? Documentation for digital signing, redaction, encryption, and protection services can be found at IronSecureDoc's official documentation page: https://ironsoftware.com/enterprise/securedoc/docs/. What C# methods are available for managing PDF annotations? IronPDF offers several C# methods for managing PDF annotations, including Add for adding, RemoveAt for removing specific annotations, and Clear for clearing all annotations. 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: 14,993,319 View Licenses