--- title: "Add sticky note annotations in C# | Nutrient .NET SDK" canonical_url: "https://www.nutrient.io/guides/dotnet/csharp/editor/add-sticky-note-annotations-to-pdf/" md_url: "https://www.nutrient.io/guides/dotnet/csharp/editor/add-sticky-note-annotations-to-pdf.md" last_updated: "2026-10-08T00:00:00.000Z" description: "How to add sticky note annotations to a PDF using Nutrient .NET SDK." --- # Adding sticky note annotations to a PDF document Use sticky note annotations to add comment markers to PDF files. Common use cases include: - Review workflows - Team feedback and commenting systems - Quality assurance notes - Collaborative document editing Sticky notes appear as icons on the page. Users can open each icon to read the full comment text. [Download sample](https://www.nutrient.io/downloads/samples/csharp/add-sticky-note-annotations-to-pdf.zip) ## How Nutrient helps Nutrient.NET SDK handles sticky note annotation structures and appearance generation. The SDK handles: - Text annotation dictionaries and popup configuration - Sticky note icon styles and appearance states - Author metadata and timestamp formatting - Popup positioning and content rendering ## Complete implementation This example adds sticky note annotations with different colors: ```csharp using Nutrient; ``` ## Working with sticky note annotations Open the document with [using statements](https://learn.microsoft.com/dotnet/csharp/language-reference/statements/using) so resources are cleaned up after processing. Then: - Create a PDF editor. - Get the page collection. - Add a letter-size page (`612 × 792`) if the document is empty. - Get the annotation collection from the first page. ```csharp try { using Document document = Document.Open("input.pdf"); using PdfEditor editor = PdfEditor.Edit(document); PdfPageCollection pages = editor.PageCollection; if (pages.Count == 0) { pages.Add(612.0f, 792.0f); } PdfPage page = pages.First?? throw new InvalidOperationException("The document has no pages."); PdfAnnotationCollection annotations = page.AnnotationCollection; ``` ## Adding a sticky note annotation Add a note with `AddStickyNote(x, y, author, subject, contents)`. In this sample: - The position is `(100, 700)`. - The metadata includes author and subject. - The contents store the full comment text. - The default note color is yellow. ```csharp PdfTextAnnotation stickyNote = annotations.AddStickyNote( 100.0f, 700.0f, "Review Author", "Review Comment", "This section needs clarification. Please add more details about the implementation." ); ``` ## Adding multiple sticky notes Add multiple notes and use color to indicate status. This sample: - Adds an urgent note at `(100, 600)` and sets it to red - Adds an approval note at `(100, 500)` and sets it to green - Uses vertical spacing to prevent icon overlap ```csharp PdfTextAnnotation urgentNote = annotations.AddStickyNote( 100.0f, 600.0f, "Reviewer", "Urgent", "This issue must be addressed before release." ); // Optionally customize the color urgentNote.Color = Color.FromArgb(255, 255, 0, 0); PdfTextAnnotation approvalNote = annotations.AddStickyNote( 100.0f, 500.0f, "Approver", "Approved", "This section looks good." ); // Optionally customize the color approvalNote.Color = Color.FromArgb(255, 0, 255, 0); ``` ## Saving the document Save the output PDF. The `catch` block catches `NutrientException` if processing fails: ```csharp editor.SaveAs("output.pdf"); Console.WriteLine("Successfully saved output.pdf"); } catch (NutrientException e) { Console.Error.WriteLine($"Error: {e.Message}"); Environment.Exit(1); } ``` ## Conclusion Use this workflow to add sticky note annotations: 1. Open the document with `using` statements for automatic resource cleanup. 2. Create an editor and access the page collection. 3. Ensure at least one page exists by adding a letter-size page if needed. 4. Retrieve the annotation collection from the target page. 5. Add sticky note annotations with coordinates, author, subject, and contents using `AddStickyNote()`. 6. Sticky notes appear as compact icons that expand into popup windows when clicked. 7. Customize colors using the `Color` property with ARGB values for color categorization. 8. Use 100-point vertical spacing between annotations to prevent icon overlap. 9. Implement color categorization workflows (red for urgent, green for approved, yellow for standard). 10. Save the document — the `using` statements release the native handles. For related annotation workflows, refer to the [.NET SDK annotation guides](https://www.nutrient.io/guides/dotnet/csharp/editor.md). --- ## Related pages - [Nutrient .NET SDK editor guides](/guides/dotnet/csharp/editor.md) - [Adding annotations to a PDF document](/guides/dotnet/csharp/editor/add-annotations-to-pdf.md) - [Adding a custom page to a PDF document](/guides/dotnet/csharp/editor/add-custom-page-to-pdf.md) - [Adding interactive form fields to a PDF document](/guides/dotnet/csharp/editor/add-form-fields-to-pdf.md) - [Adding free text annotations to a PDF document](/guides/dotnet/csharp/editor/add-freetext-annotations-to-pdf.md) - [Adding invisible digital signatures to a PDF document](/guides/dotnet/csharp/editor/add-invisible-signature-to-pdf.md) - [Adding link annotations to a PDF document](/guides/dotnet/csharp/editor/add-link-annotations-to-pdf.md) - [Adding redaction annotations to a PDF document](/guides/dotnet/csharp/editor/add-redaction-annotations-to-pdf.md) - [Adding shape annotations to a PDF document](/guides/dotnet/csharp/editor/add-shape-annotations-to-pdf.md) - [Adding stamp annotations to a PDF document](/guides/dotnet/csharp/editor/add-stamp-annotations-to-pdf.md) - [Adding text markup annotations to a PDF document](/guides/dotnet/csharp/editor/add-text-markup-annotations-to-pdf.md) - [Adding visible digital signatures to a PDF document](/guides/dotnet/csharp/editor/add-visible-signature-to-pdf.md) - [Advanced digital signature workflows](/guides/dotnet/csharp/editor/advanced-digital-signatures.md) - [Detecting and adding form fields to a PDF document](/guides/dotnet/csharp/editor/detect-and-add-form-fields.md) - [Editing PDF form fields](/guides/dotnet/csharp/editor/editing-pdf-form-fields.md) - [Editing PDF metadata with Nutrient .NET SDK](/guides/dotnet/csharp/editor/editing-pdf-metadata.md) - [Filling PDF form fields](/guides/dotnet/csharp/editor/fill-pdf-form.md) - [Managing PDF page order](/guides/dotnet/csharp/editor/manage-pdf-page-order.md) - [Merging PDFs](/guides/dotnet/csharp/editor/merge-pdf-into-other-pdf.md)