While making WCF service you need to ensure that all errors needs to be logged .

For doing that we will need to use a operation contract called fault tolerance

[ServiceContract]
public interface ISimpleService
{
               [OperationContract]
               string SimpleOperation();
}
public class SimpleService : ISimpleService
{
              public string SimpleOperation()
             {
                  //Some code here
                  throw new Exception(Exception occurred at service level : SimpleOperation error);
             }
}

[DataContract]
public class CustomFaultDetails
{
            [DataMember]
            public string ErrorID { get; set; }
           
            [DataMember]
            public string ErrorDetails { get; set; }
}

We can track the error details by creating model class for the error which contains its type and details