The url() function is used to return the Url class which is used to manage urls. It takes only one argument which is the test url and returns the instance of the Url class. You can learn more about url class from here

  url('http://site.com/users#profile')->hash(); // profile 
                  

  url('http://site.com/users?val=foo&var=bar')->query(); // ['val'=>'foo', 'var'=> 'bar']  
                  

  vdump( url('index')->is('index') ); // true