public class ShowOrders
    {
        private readonly string email;

        ShowOrders(string email)
        {
            this.email = email;
        }

        public void Show()
        {
            using(Technic context = new Technic())
            {
                var findedRecords = context.Customers.Where(r => r.Email == this.email);
                if(findedRecords.Count() > 0)
                {
                    foreach(var item in findedRecords)
                    {
                        Console.WriteLine($"Id: {item.Id} Name: {item.Name} Age: {item.Age}");
                    }
                }
            }
        }
    }

public class Customer
{
    public int Id { get; set; }
    [Required]
    public string Name { get; set; }
    [StringLength(45)]
    public string Email { get; set; }
    public int Age { get; set; }

    // Ссылка на заказы
    public virtual List<Order> Orders { get; set; }
}