Where does PdfAnnotation live in the IronPDF API?

PdfAnnotation is in the IronPdf.Annotations namespace, shipped in IronPdf.dll.

What is the PdfAnnotation class used for in C#?

PdfAnnotation is the IronPDF class that base PDF annotation. It is part of the IronPdf.Annotations namespace and is used through the IronPDF C# API.

What are the key properties of PdfAnnotation?

Properties commonly used on PdfAnnotation include Color, Contents, Hidden, Name. Each property configures one aspect of the PDF annotations surface exposed by the class.

Class PdfAnnotation

Base PDF annotation

Inheritance

System.Object

PdfAnnotation

PdfFreeTextAnnotation

PdfLinkAnnotation

PdfTextAnnotation

Namespace: IronPdf.Annotations

Assembly: IronPdf.dll

Syntax

public abstract class PdfAnnotation : Object

PdfAnnotation is the object IronPDF C# code works with for PDF annotations. It represents base PDF annotation.

PdfAnnotation matters when an application needs to configure or invoke PDF annotations from C# code. The class encapsulates the related options and behavior in a single object that is set up once and reused across render or processing calls. Typical scenarios include batch generation pipelines, templated document workflows, and integration with existing C# document services.

To use PdfAnnotation, instantiate or obtain it from the relevant entry point in the IronPDF C# API. Key properties include Color, Contents, Hidden, Name. Assign options or invoke methods on the instance to configure or perform the operation. The base URLs covers typical usage in C# end to end.

using IronPdf;

// Obtain PdfAnnotation from the relevant entry point in the IronPDF API
void Configure(PdfAnnotation instance)
{
    var current = instance.Color;
}

For the broader workflow, see the IronPDF C# documentation for related how-to guides and examples. For broader context, the PDF annotations portion of the IronPDF C# API contains related types that work with PdfAnnotation directly. PdfAnnotation exposes additional members beyond those highlighted above; the reference tables on this page list the full set. In application code, treat PdfAnnotation as a configured object that is constructed once and reused across operations rather than instantiated per call. Configuration is generally idempotent: assigning the same property value twice has the same effect as assigning it once. For diagnostic purposes, inspect the relevant PdfAnnotation property after each operation to confirm the configured state. See the constructors, properties, and methods tables below for the complete API surface of PdfAnnotation. Application code typically obtains or instantiates a single PdfAnnotation and shares it across multiple IronPDF operations rather than recreating it per call.

Properties

Color

Annotation Color

Declaration

public Color Color { get; }

Property Value

Type	Description
IronSoftware.Drawing.Color

Text to be displayed for the annotation or, if this type of annotation does not display text, an alternate description of the annotationâ€™s contents in human-readable form.

Declaration

public string Contents { get; }

Property Value

Type	Description
System.String

Hidden

Annotation visibility status

Declaration

public bool Hidden { get; set; }

Property Value

Type	Description
System.Boolean

Name

The annotation name, a text string uniquely identifying it among all the annotations on its page.

Declaration

public string Name { get; }

Property Value

Type	Description
System.String

Rectangle

Declaration

public Rectangle Rectangle { get; }

Property Value

Type	Description
IronSoftware.Drawing.Rectangle

Type

Annotation type

Declaration

public PdfAnnotationType Type { get; }

Property Value

Type	Description
PdfAnnotationType