php artisan make:auth is no longer in laravel 6.x
From this tutorial you are going to learn the new laravel authentication system.

First install laravel project 

laravel new laravel6-auth

After installing the project run the command bellow

cd laravel6-auth
php artisan serve

Now browse in your favorite browser

http://localhost:8000/

Next install laravel ui package.

composer require laravel/ui --dev

Now you need to run one of the command bellow to generate login/registration scaffolding

php artisan ui bootstrap --auth
php artisan ui vue --auth
php artisan ui react --auth

But if you click login or register you will see like this.

Now run the following commands.

npm install
npm run dev

Click on register button.
Finally we are done :)