Below given function is use for send mail.
Private Sub mail()
Const ToAddress As String = "//sender address"
Dim mm As New System.Net.Mail.MailMessage(ToAddress, Email.Text)
mm.Subject = "Registration"
mm.IsBodyHtml = True
mm.Body = "//Your message"
Dim smtp As New System.Net.Mail.SmtpClient()
smtp.Send(mm)
End Sub
Now you configure the smtp in web.config file:-
<system.net>
<mailsettings>
<smtp>
<network host="mail.google.com//write your host name" port="//write your mail prort no" username="//write your mailaddress for sending mail" password="//write your mail password" />
</smtp>
</mailsettings>
</system.net>