You can select "Plane Geometry" from the "AutoShapes" in the sidebar , hold down the left mouse button and drag out an ellipse in the canvas.

If you want to draw an ellipse accurately, please click the menu "Drawing" > "Ellipse" to pop up the "Input Ellipse Parameters" panel.

Enter the center coordinates (the format is "x-axis coordinate" + "," + "y-axis coordinate") and the sizes of the major and minor semi-axis.