For example you have a controller with name
AuthController and a method
showLoginPage which is used to show login page.
So you don't want url like
example.com/authcontroller/showloginpage, but want it be like:
example.com/login which should show login page.
To do this at first disable auto discovery functionality in Routes file:
$routes->setAutoRoute(false);
After add this route to your routes file inside App/config folder:
$routes->group('', function ($routes) {
$routes->get('login', 'AuthController :: showLoginPage');
});