public static Envelope CreateEnvelope( 
   Envelope envelope,
   SpatialReference spatialReference
)

{
  // Use a builderEx convenience method or use a builderEx constructor.

  MapPoint minPt = MapPointBuilderEx.CreateMapPoint(1.0, 1.0);
  MapPoint maxPt = MapPointBuilderEx.CreateMapPoint(2.0, 2.0);

  // Create an envelope
  Envelope env = EnvelopeBuilderEx.CreateEnvelope(minPt, maxPt);

  Polygon polygonFromEnv = PolygonBuilderEx.CreatePolygon(env);

  PolygonBuilderEx polygonBuilderEx = new PolygonBuilderEx(env);
  polygonBuilderEx.SpatialReference = SpatialReferences.WGS84;
  polygonFromEnv = polygonBuilderEx.ToGeometry() as Polygon;
}

{
  //Note: Must be on QueuedTask.Run

  //Build geometry
  Coordinate2D ll = new Coordinate2D(1.0, 4.75);
  Coordinate2D ur = new Coordinate2D(3.0, 5.75);
  Envelope env = EnvelopeBuilderEx.CreateEnvelope(ll, ur);

  //Set symbology, create and add element to layout
  CIMStroke outline = SymbolFactory.Instance.ConstructStroke(
    ColorFactory.Instance.BlackRGB, 5.0, SimpleLineStyle.Solid);
  CIMPolygonSymbol polySym = SymbolFactory.Instance.ConstructPolygonSymbol(
    ColorFactory.Instance.GreenRGB, SimpleFillStyle.DiagonalCross, outline);

  var ge = GraphicFactory.Instance.CreateSimpleGraphic(env, polySym);
  var elemInfo = new ElementInfo()
  {
    Anchor = Anchor.CenterPoint,
    Rotation = 45.0,
    CornerRounding = 5.0
  };

  ElementFactory.Instance.CreateGraphicElement(
    layout, env, polySym, "New Rectangle", false, elemInfo);
}

{
  //Create a simple 2D rectangle graphic and apply simple fill and
  //outline symbols.

  //Note: Must be on QueuedTask.Run

  //Build 2D envelope geometry
  Coordinate2D rec_ll = new Coordinate2D(1.0, 4.75);
  Coordinate2D rec_ur = new Coordinate2D(3.0, 5.75);

  Envelope rec_env = EnvelopeBuilderEx.CreateEnvelope(rec_ll, rec_ur);

  //Set symbology, create and add element to layout
  CIMStroke outline = SymbolFactory.Instance.ConstructStroke(
    ColorFactory.Instance.BlackRGB, 5.0, SimpleLineStyle.Solid);
  CIMPolygonSymbol polySym = SymbolFactory.Instance.ConstructPolygonSymbol(
    ColorFactory.Instance.GreenRGB, SimpleFillStyle.DiagonalCross, outline);


  GraphicElement recElm = ElementFactory.Instance.CreateGraphicElement(
    layout, rec_env, polySym, "New Rectangle");
  //Or use Predefined shape
  GraphicElement recElm2 = ElementFactory.Instance.CreatePredefinedShapeGraphicElement(
                            layout, PredefinedShape.Rectangle, rec_env, polySym,
                            "New Rectangle2");
}

{
  //Create a simple point text element and assign basic symbology and text settings.

  //Note: Must be on QueuedTask.Run
  //Build 2D point geometry
  Coordinate2D coord2D = new Coordinate2D(3.5, 10);

  //Set symbology, create and add element to layout
  CIMTextSymbol sym = SymbolFactory.Instance.ConstructTextSymbol(
                ColorFactory.Instance.RedRGB, 32, "Arial", "Regular");
  string textString = "Point text";

  //use ElementInfo to set placement properties during create
  var elemInfo = new ElementInfo()
  {
    Anchor = Anchor.CenterPoint,
    Rotation = 45
  };
  var ptTxtElm = ElementFactory.Instance.CreateTextGraphicElement(
    layout, TextType.PointText, coord2D.ToMapPoint(), sym, textString,
                       "New Point Text", true, elemInfo);

  //Change additional text properties
  ptTxtElm.SetX(4.5);
  ptTxtElm.SetY(9.5);
}

{
  //Create a map frame and set its camera by zooming to the extent of an existing bookmark.
  //Construct on the worker thread

  //Build 2D envelope geometry
  Coordinate2D mf_ll = new Coordinate2D(6.0, 8.5);
  Coordinate2D mf_ur = new Coordinate2D(8.0, 10.5);
  Envelope mf_env = EnvelopeBuilderEx.CreateEnvelope(mf_ll, mf_ur);

  //Reference map, create MF and add to layout
  MapProjectItem mapPrjItem = Project.Current.GetItems<MapProjectItem>()
                       .FirstOrDefault(item => item.Name.Equals("Map"));
  Map mfMap = mapPrjItem.GetMap();
  Bookmark bookmark = mfMap.GetBookmarks().FirstOrDefault(
                        b => b.Name == "Great Lakes");

  MapFrame mfElm = ElementFactory.Instance.CreateMapFrameElement(
                       layout, mf_env, mfMap, "New Map Frame");

  //Zoom to bookmark
  mfElm.SetCamera(bookmark);
}