Using C# PDF SDK
C# PDF Builder: How to draw, add a curve shape to PDF file

...
PDFContext ctx = new PDFContext();
//  set figure size: width 600 pixels; height 300 pixels
ctx.SetWidth(new RELength(600, Units.PX));
ctx.SetHeight(new RELength(300, Units.PX));
//  draw a heart
REPath path = new REPath();
path.AddBezier(200, 110, 200, 70, 270, 60, 300, 110);
path.AddBezier(300, 110, 330, 60, 400, 70, 400, 110);
path.AddBezier(400, 110, 400, 150, 380, 200, 300, 250);
path.AddBezier(300, 250, 220, 200, 200, 150, 200, 110);
path.CloseAllPath();
ctx.FillPath(new RESolidBrush(new REColor(255, 0, 0)), path);
ctx.DrawPath(new REPen(new REColor(224, 224, 0), 3F), path);
Figure figure = new Figure(ctx);
...

String outputFilePath = Program.RootPath + "\\" + "Sample25.pdf";

Document document = new Document();
PDFBuildHandler.Create(document, outputFilePath);
//  open document
document.Open();
//  create Figure
PDFContext ctx = new PDFContext();
...
...
Figure figure = new Figure(ctx);
document.Add(figure);
//  close document and save to the output file
document.Close();