yii2-app-basic/views/site/login.php

<?php
use yii\helpers\Html;
use yii\widgets\ActiveForm;

/**
 * @var yii\base\View $this
 * @var yii\widgets\ActiveForm $form
 * @var app\models\LoginForm $model
 */
$this->title = 'Login';
$this->params['breadcrumbs'][] = $this->title;
?>
<h1><?php echo Html::encode($this->title); ?></h1>

<p>Please fill out the following fields to login:</p>

<div class="row">
	<div class="col-lg-3">
		<?php $form = ActiveForm::begin(array('id' => 'login-form')); ?>
			<?php echo $form->field($model, 'username')->textInput(); ?>
			<?php echo $form->field($model, 'password')->passwordInput(); ?>
			<?php echo $form->field($model, 'rememberMe', array('options' => array('class' => 'checkbox')))->checkbox(); ?>
			<div class="form-actions">
				<?php echo Html::submitButton('Login', array('class' => 'btn btn-primary')); ?>
			</div>
		<?php ActiveForm::end(); ?>
	</div>
</div>