C# .net EMail processing

Here is an example for Gmail to send a mail:

using System.Net.Mail;
using System.Net;

            var fromAddress = new MailAddress("from@gmail.com", "From Name");
            var toAddress = new MailAddress("to@yahoo.com", "To Name");
            const string fromPassword = "password";
            const string subject = "test";
            const string body = "Hey now!!";

            var smtp = new SmtpClient
            {
                Host = "smtp.gmail.com",
                Port = 587,
                EnableSsl = true,
                DeliveryMethod = SmtpDeliveryMethod.Network,
                Credentials = new NetworkCredential(fromAddress.Address, fromPassword),
                Timeout = 20000
            };
            using (var message = new MailMessage(fromAddress, toAddress)
            {
                Subject = subject,
                Body = body
            })
            {
                smtp.Send(message);
            }

There is also an API that you may want to use:
https://developers.google.com/google-apps/gmail/[^]

Sending the mail should be identical for most email providers. Displaying the inbox may be different for each, so you may want to search for an API depending on which provider you use.