sudo apt install nodejs npm
npm install puppeteer

await page.type('#search .form input[name="search_word"]', 'Puppeteer');
await page.click('#search .form input[id="hnaviSearchSubmit"]');

<div id="search">
  <div class="form">
    <form action="./search/" method="get">
      <input type="hidden" name="search_menu" value="keyword">
      <input type="hidden" name="tab" value="3">
      <input type="text" name="search_word" value="" id="hnaviSearchWord" placeholder="キーワードを入力" />
      <input type="submit" id="hnaviSearchSubmit" value="" />
...(略)