using DataDynamics.ActiveReports.Viewer.Annotations;

rptAnnotations rpt = new rptAnnotations();
private void AddAnnotations()
{
   //Run the report first
   rpt.Run();
   
   //Assign the viewer
   this.viewer1.Document = rpt.Document;
   
   //Create an annotation and assign property values
   AnnotationCircle circle = new AnnotationCircle();
   circle.Color = System.Drawing.Color.GreenYellow;
   circle.Border.Color = System.Drawing.Color.Chartreuse;
  
   //Add the annotation
   circle.Attach(1,1); //screen location
   this.viewer1.Document.Pages[0].Annotations.Add(circle);

   //Set the size properties. The annotation must be added to the page first.
   circle.Height = 0.25f;
   circle.Width = 0.50f;

   //Save annotations to an RDF file
   rpt.Document.Save("C:\\MyAnnotations.rdf");
}