c# application add mail service
var mailMessage = new MimeMessage();
mailMessage.From.Add(new MailboxAddress("from name", "from email"));
mailMessage.To.Add(new MailboxAddress("to name", "to email"));
mailMessage.Subject = "subject";
mailMessage.Body = new TextPart("plain")
{
Text = "Hello"
};
using (var smtpClient = new SmtpClient())
{
smtpClient.Connect("smtp.gmail.com", 587, true);
smtpClient.Authenticate("user", "password");
smtpClient.Send(mailMessage);
smtpClient.Disconnect(true);
}