To draw an ellipse, use the drawEllipse() method in C# that belong to the Graphics object. It has a pen object as well as a rectangle object.
You need windows form to draw shapes in C#.
Set graphics object.
Graphics g = this.CreateGraphics();
Now, the pen object.
Pen p = new Pen(new SolidBrush(Color.Red), 15);
The following is the rectangle object.
Rectangle r = new Rectangle(120, 60, 180, 180);
Now use the drawEllipse() method with the graphics object and add both the objects in it to draw an ellipse.