How to logout and redirect to login page using Laravel 5.4?

In your web.php (routes):

add:

Route::get('logout', '\App\Http\Controllers\Auth\LoginController@logout');

In your LoginController.php

add:

public function logout(Request $request) {
  Auth::logout();
  return redirect('/login');
}

Also, in the top of LoginController.php, after namespace

add:

use Auth;

Now, you are able to logout using yourdomain.com/logout URL or if you have created logout button, add href to /logout

Well even if what suggest by @Tauras just works I don't think it's the correct way to deal with this.

You said you have run php artisan make:auth which should have also inserted Auth::routes(); in your routes/web.php routing files. Which comes with default logout route already defined and is named logout.

You can see it here on GitHub, but I will also report the code here for simplicity:

    /**
     * Register the typical authentication routes for an application.
     *
     * @return void
     */
    public function auth()
    {
        // Authentication Routes...
        $this->get('login', 'Auth\LoginController@showLoginForm')->name('login');
        $this->post('login', 'Auth\LoginController@login');
        $this->post('logout', 'Auth\LoginController@logout')->name('logout');
        // Registration Routes...
        $this->get('register', 'Auth\RegisterController@showRegistrationForm')->name('register');
        $this->post('register', 'Auth\RegisterController@register');
        // Password Reset Routes...
        $this->get('password/reset', 'Auth\ForgotPasswordController@showLinkRequestForm')->name('password.request');
        $this->post('password/email', 'Auth\ForgotPasswordController@sendResetLinkEmail')->name('password.email');
        $this->get('password/reset/{token}', 'Auth\ResetPasswordController@showResetForm')->name('password.reset');
        $this->post('password/reset', 'Auth\ResetPasswordController@reset');
    }

Then again please note that logout requires POST as HTTP request method. There are many valid reason behind this, but just to mention one very important is that in this way you can prevent cross-site request forgery.

So according to what I have just pointed out a correct way to implement this could be just this:

<a href="{{ route('logout') }}" onclick="event.preventDefault(); document.getElementById('frm-logout').submit();">
    Logout
</a>    
<form id="frm-logout" action="{{ route('logout') }}" method="POST" style="display: none;">
    {{ csrf_field() }}
</form>

Finally note that I have inserted laravel out of the box ready function {{ csrf_field() }}!