If you want to send email using your Gmail account or using Gmail's smtp server in ASP.NET application or if you don't have a working smtp server to send mails using your ASP.NET application or aspx page than sending e-mail using Gmail is best option.you need to write code like this First of all add below mentioned namespace in code behind of aspx page from which you want to send the mail.using System.Net.Mail;Now write this code in click event of button C# code protected void Button1_Click(object sender, EventArgs e){  MailMessage mail = new MailMessage();  mail.To.Ad...