users.php

class Users
{
    private $id       = null;

    private $login    = null;
    private $password = null;

    public function __construct($login, $password)
    {
         $this->login       = $login;
         $this->password    = $password;
    }

    // All Setters && Getters for all cells of db
    // a.g public function SetLogin; public function GetLogin

    static public function getInstance($id)
    {
         $row = "SELECT * FROM `users` WHERE `id` = '{$id}' ";
         if($row){
              $obj = new Users($row['login'], $row['password']);
              $obj->setId($row['id']);
              return $obj;
         }
    }
}

class Users
{
  private $id       = null;

  private $login    = null;
  private $password = null;

  public function __construct(...$fields)
  {
    $this->login       = $fields[0];
    $this->password    = $fields[1];
  }
  ...
}
$user = new Users('hello', 'world');
echo "<pre>";
print_r($user);

class Users
{
  private $id       = null;

  private $login    = null;
  private $password = null;

  public function __construct($fields)
  {
    foreach($fields as $key => $value) {
      $this->$key       = $value;
    }
  }
  // ...
}
$user = new Users(['login' => 'hello', 'password' => 'world']);
echo "<pre>";
print_r($user);