Understanding how Func<T> works.

funcs.cs

using System;
                    
public class Program
{
    public static void Main() { 
        new Functions().Start();    
    }
}

public class Functions 
{   
    public void Start() 
    {
        var step = new ServiceInitializationStep (
                    () => "this is a string",
                    () => "this is another string",
                    (number) => "this is yet another string " + number.ToString()
        );
        
        step.PrintData();
    }
}

public class ServiceInitializationStep 
{
    public ServiceInitializationStep(Func<string> securedString, Func<string> securedConnectionString, Func<int, string> securedNewConnectionString)
    {
        _securedString = securedString;
        _securedConnectionString = securedConnectionString;
        _securedNewConnectionString = securedNewConnectionString;
    }
    
    public void PrintData() {
        Console.WriteLine("test");
        Console.WriteLine(_securedString());
        Console.WriteLine(_securedConnectionString());
        Console.WriteLine(_securedNewConnectionString(100));
    }
    
    private Func<string> _securedString { get; set; }
    private Func<string> _securedConnectionString { get; set; }
    private Func<int, string> _securedNewConnectionString { get; set; }
}

Here we can see this code running on https://dotnetfiddle.net/lJykOK