Below is a sample code snippet of the button click event which launches the Email App and then creates a new Message with the specified email address.
Sending Email using URI LaunchUriAsync in Windows Phone 8
async private void Button_Click_1(object sender, RoutedEventArgs e)
{
await Launcher.LaunchUriAsync(new Uri("mailto:[email protected]"));
}Once the Email App is launched, the user can type the message and tap the send icon to send the email.