JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/autosize.js/3.0.20/autosize.min.js"></script>
<form action="">
  <input type="text" placeholder="請輸入暱稱.."><br>
  <textarea name="" id="" cols="20" rows="3"></textarea><br>
  <button>送出</button>
</form>

CSS

input, textarea, button{
  margin-top: 10px;
}

JavaScript

autosize(document.querySelector("textarea"));