Question

Can Windows service be used for fetching data from DB and mailing(around 300 mails) giving a 15 minutes time interval with a timer?

Is Windows service a good option to use for this scenario.?

Answer 1

If the program amounts to:

while (true)
{
    SendEmailsFromDatabase();
    Thread.Sleep(TimeSpan.FromMinutes(15));
}

Then you don’t want a Windows service. You want a console application and a scheduled task. See Programs are not cats.