how to create bar code

You can try using BarcodeReader class from LEADTOOLS to read one or more barcodes from an image.
For example, the following code reads all barcodes in an image:
+------------------------+
using(RasterImage image = codecs.Load(imageFileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1))
{
// Read all the barcodes in this image
BarcodeData[] barcodes = reader.ReadBarcodes(image, LogicalRectangle.Empty, 0, null);

// Print out the barcodes we found
Console.WriteLine("{0} contains {1} barcodes", imageFileName, barcodes.Length);
for(int i = 0; i < barcodes.Length; i++)
{
BarcodeData barcode = barcodes[i];
Console.WriteLine(" {0} - {1} - {2}", i + 1, barcode.Symbology, barcode.Value);
}
Console.WriteLine("-----------------");
}
+------------------------+
You can use the above code in your ASP.NET server side code, or in a web-service.

You can find more details in the following online links:
https://www.leadtools.com/help/leadtools/v19m/dh/ba/barcodereader.html

Also, check the following online barcode demo:
http://demo.leadtools.com/JavaScript/Barcode/index.html