public class CIMReportField : CIMTableField, System.ComponentModel.INotifyPropertyChanged, System.Xml.Serialization.IXmlSerializable  

{
  //Note: Call within QueuedTask.Run()
  //The fields in the datasource used for the report
  //This uses a US Cities dataset
  var listFields = new List<CIMReportField> {
          //Grouping should be the first field
          new CIMReportField{Name = "STATE_NAME", FieldOrder = 0, Group = true, SortInfo = FieldSortInfo.Desc}, //Group cities using STATES
          new CIMReportField{Name = "CITY_NAME", FieldOrder = 1},
          new CIMReportField{Name = "POP1990", FieldOrder = 2, },
      };
  //Definition query to use for the data source
  var defQuery = "STATE_NAME LIKE 'C%'";
  //Define the Datasource
  var reportDataSource = new ReportDataSource(featureLayer, defQuery, listFields);
  //The CIMPage defintion - page size, units, etc
  var cimReportPage = new CIMPage
  {
    Height = 11,
    StretchElements = false,
    Width = 6.5,
    ShowRulers = true,
    ShowGuides = true,
    Margin = new CIMMargin { Bottom = 1, Left = 1, Right = 1, Top = 1 },
    Units = LinearUnit.Inches
  };

  //Report template
  var reportTemplates = await ReportTemplateManager.GetTemplatesAsync();
  var reportTemplate = reportTemplates.Where(r => r.Name == "Attribute List with Grouping").First();

  //Report Styling
  var reportStyles = await ReportStylingManager.GetStylingsAsync();
  var reportStyle = reportStyles.Where(s => s == "Cool Tones").First();

  //Field Statistics
  var fieldStatisticsList = new List<ReportFieldStatistic> {
          new ReportFieldStatistic{ Field = "POP1990", Statistic = FieldStatisticsFlag.Sum}
          //Note: NoStatistics option for FieldStatisticsFlag is not supported.
      };
  var newReport = ReportFactory.Instance.CreateReport("USAReport", reportDataSource, cimReportPage, fieldStatisticsList, reportTemplate, reportStyle);
}

{
  //This is the gap between two fields
  double fieldIncrement = 0.9388875113593206276389;
  //On the QueuedTask
  //New field to add.
  var newReportField = new CIMReportField
  {
    Name = "POP1990",
    FieldOrder = 2,
  };
  //Get the "ReportSection element"				
  var mainReportSection = report.Elements.OfType<ReportSection>().FirstOrDefault();
  if (mainReportSection == null) return;

  //Get the "ReportDetails" within the ReportSectionElement. ReportDetails is where "fields" are.
  var reportDetailsSection = mainReportSection?.Elements.OfType<ReportDetails>().FirstOrDefault();
  if (reportDetailsSection == null) return;

  //Within ReportDetails find the envelope that encloses a field.
  //We get the first CIMParagraphTextGraphic in the collection so that we can add the new field next to it.					
  var lastFieldGraphic = reportDetailsSection.Elements.FirstOrDefault((r) =>
  {
    var gr = r as GraphicElement;
    if (gr == null) return false;
    return (gr.GetGraphic() is CIMParagraphTextGraphic ? true : false);
  });
  //Get the Envelope of the last field
  var graphicBounds = lastFieldGraphic.GetBounds();

  //Min and Max values of the envelope
  var xMinOfFieldEnvelope = graphicBounds.XMin;
  var yMinOfFieldEnvelope = graphicBounds.YMin;

  var xMaxOfFieldEnvelope = graphicBounds.XMax;
  var YMaxOfFieldEnvelope = graphicBounds.YMax;
  //create the new Envelope to be offset from the existing field

  MapPoint newMinPoint = MapPointBuilderEx.CreateMapPoint(xMinOfFieldEnvelope + fieldIncrement, yMinOfFieldEnvelope);
  MapPoint newMaxPoint = MapPointBuilderEx.CreateMapPoint(xMaxOfFieldEnvelope + fieldIncrement, YMaxOfFieldEnvelope);
  Envelope newFieldEnvelope = EnvelopeBuilderEx.CreateEnvelope(newMinPoint, newMaxPoint);

  //Create field
  GraphicElement fieldGraphic = ReportElementFactory.Instance.CreateFieldValueTextElement(reportDetailsSection, newFieldEnvelope, newReportField);
}