If you create a new project, WCF Service Application C#, it makes a web service and starts it up.
But there is no information on how to actually communicate with it from
How to make a UWP that will work with the default WCF Service application
Create a default WCF Service application and start it up as you have already did.
Create a Universal Windows Blank App by following Create a "Hello, world" app (XAML) in the same solution.
Add following code to a button click event handle.Then run uwp you will see the GetData
Result.
private async void BtnConnectWcf_Click(object sender, RoutedEventArgs e)
{
ToDoService.Service1Client client = new ToDoService.Service1Client();
await new Windows.UI.Popups.MessageDialog(client.GetDataAsync(10).Result.ToString()).ShowAsync();
await client.CloseAsync();
}