I have generated a pdf using iTextSharp, when its created it saves automatically in the location provided in my code on the server not on the client side and of course witho
Currently you are saving your file on the file server, thereby overwriting the same pdf with every request. And probably causing errors if you get two requests for a PDF at the same time.
Use Response to return the PDF (from the memorystream) to the user, and skip the writing of the PDF to a file locally on your server.
The browser will ask the user where the file should be saved. Something like:
Response.ContentType = "Application/pdf";
myMemoryStream.CopyTo(Response.OutputStream);
Also look at the answer from Alun, using content-disposition you can propose a filename to the user.