what does strip tags does in php code example

Example 1: php strip tags

<?php
$text = '<p>Test paragraph.</p><!-- Comment --> <a href="#fragment">Other text</a>';
echo strip_tags($text);
//Test paragraph. Other text

// Allow <p> and <a>
echo strip_tags($text, '<p><a>');
//<p>Test paragraph.</p> <a href="#fragment">Other text</a>
// as of PHP 7.4.0 the line above can be written as:
// echo strip_tags($text, ['p', 'a']);
?>

Example 2: remove html from string php

echo strip_tags("Hello <b>world!</b>");