The Microsoft .NET framework provides two namespaces, System.Net and System.Net.Sockets to send or receive data over the Internet. SMTP protocol is using for sending email from C#. C# use System.Net.Mail namespace for sending email.To send e-mail you need to configure SMTP server. If you don’t have any SMTP, you can use free SMTP server. You can also use your gmail account.
More details with example: http://cybarlab.blogspot.com/2013/03/send-e-mail-using-c-sharp.html
Hope it will help you.
Tanks & best regard