Step 1: Create a new project called FreeSms
Step 2: Design your form as below

Add code to handle btnSend event click
private void btnSend_Click(object sender, EventArgs e)
{
try
{
SmtpClient smtp = new SmtpClient();
MailMessage message = new MailMessage();
smtp.Credentials = new NetworkCredential(txtUsername.Text, txtPassword.Text);
smtp.Host = "ipipi.com";
message.From = new MailAddress(string.Format("{0}@ipipi.com", txtUsername.Text));
message.To.Add(string.Format("{0}@sms.ipipi.com", txtPhone.Text));
message.Subject = "FoxLearn";
message.Body = txtMessage.Text;
smtp.Send(message);
MessageBox.Show("Your message has been successfully sent.", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
To play demo, you need to create an account at ipipi website
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