How to properly add a new style to head in YII2?

Question

Yii

by default, the head(main.php) section in YII2 works like this:

<title><?= Html::encode($this->title) ?></title>
    <?php $this->head() ?>
  </head>

I understand that I can just write the style like this:

<title><?= Html::encode($this->title) ?></title>
    <?php $this->head() ?>
  <link rel="stylesheet" href="путь до ссылки">
  </head>

but as I understand it, this is not the only way, since there is a HEAD () function, it is written somewhere and it loads the styles.
Where is this function located and how does it work?
But enough to answer where it is)

Answer 1

/assets/AppAsset.php <=