Argument 1 passed to App\Http\Controllers\Auth\LoginController::credentials() must be an instance of App\Http\Controllers\Auth\Request, instance of Illuminate\Http\Request given, called in C:\xampp\htdocs\laravel-ecommerce\vendor\laravel\ui\auth-backend\AuthenticatesUsers.php on line 83

Go to your Login Controller and add below class.

use \Illuminate\Http\Request;