If the barcode is an image you use the DrawImage method, passing the image and coordinates. If you are using C1Barcode control then the image is easily attainable.
_c1pdf.DrawImage(c1BarCode1.Image,
new RectangleF(100, 100, 30, 20));
If the barcode is a value using a barcode font, you have to set the FontType to Embeded and use DrawString with the embedded barcode font. Note that the font must be installed on your machine.
_c1pdf.DrawString(
"123456", new Font("Name of font", 28), Brushes.Black, new PointF(200, 200));
Regards,
Greg L