Webrequest populate UserAgent and Headers

asp net version 2.0

asp.net forms with vb.net

       Dim strData As String = String.Empty
            Dim wr As HttpWebRequest = Nothing
            Dim wrRes As HttpWebResponse = Nothing                  

  wr = DirectCast(WebRequest.Create(URi), HttpWebRequest)
                    wr.Timeout = TimeOut 'Milliseconds default is 3 minutes 180,000
                    wr.Credentials = System.Net.CredentialCache.DefaultCredentials
                    wr.Method = WebRequestMethods.Http.Get
                    wr.KeepAlive = True
                    wr.Headers.Add(HttpRequestHeader.Cookie, CookieHeader)
                    wrRes = DirectCast(wr.GetResponse(), HttpWebResponse)
                    Using strReader As StreamReader = New StreamReader(wrRes.GetResponseStream())
                        strData = strReader.ReadToEnd
                        strReader.Close()
                    End Using

I want to add

wr.UserAgent = ??
wr.Header = ??

Or is it wr.UserAgent.add ??

To show to URL request is coming via browser address bar and not a api call..

Question

1. How do I populate wr.UserAgent to allow 'All user agents" like /
2. How do I populate wr.Header with my browser header information

thx