You can use Web API. If you want a simple communication then you can use the following method-
private static void PostData()
{
HttpWebRequest httpWReq = (HttpWebRequest)WebRequest.Create("http://yourdomain.com/yourpage.aspx");
ASCIIEncoding encoding = new ASCIIEncoding();
string postData = "extension=rayhan";
postData += "&type=0";
byte[] data = encoding.GetBytes(postData);
httpWReq.Method = "POST";
httpWReq.ContentType = "application/x-www-form-urlencoded";
httpWReq.ContentLength = data.Length;
using (Stream stream = httpWReq.GetRequestStream())
{
stream.Write(data, 0, data.Length);
}
HttpWebResponse response = (HttpWebResponse)httpWReq.GetResponse();
string responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
response.Close();
}