Saving Textarea Value After Submission in PHP

Let's now make the content of textarea persist after submission:

html<form action="" method="GET">
  <textarea name="test"><?= $_GET['test'] ?? '' ?></textarea>
  <input type="submit">
</form>

Задание 1

Let Russian text be entered into textarea. After form submission, display the transliteration of this text. Make sure that the form content persists after submission.