✅ how to move it to abstract class

public abstract class Login
{
  void Login();
}

public class AdminLogin : Login
{
  public void override Login()
  {
    // same as what you already have, including user input
  }
}

public class UserLogin : Login
{
  public void override Login()
  {
    // you can do this differently than in the AdminLogin class, assuming that users login differently to admins
  }
}

public abstract class Login
{
  void Login();
}

public class AdminLogin : Login
{
  public void override Login()
  {
    // same as what you already have, including user input
  }
}

public class UserLogin : Login
{
  public void override Login()
  {
    // you can do this differently than in the AdminLogin class, assuming that users login differently to admins
  }
}

var logins = new List<Login>();

// We can treat both classes as if they were the same and put them in the same list.
logins.Add(new AdminLogin());
logins.Add(new UserLogin());

// Because we can treat both classes as if they are the same, we can call the methods common to both of them - the methods in the abstract class
foreach (var login in logins)
{
  login.Login();
}

var logins = new List<Login>();

// We can treat both classes as if they were the same and put them in the same list.
logins.Add(new AdminLogin());
logins.Add(new UserLogin());

// Because we can treat both classes as if they are the same, we can call the methods common to both of them - the methods in the abstract class
foreach (var login in logins)
{
  login.Login();
}