JSFiddle - React, Tailwind, and code Playground

HTML

<div contenteditable="true">
</div>
<button id="bold">
Bold
</button>

CSS

div {
  width: 100%;
  height: 400px;
  padding: 15px;
  background: #eee;
}

JavaScript

bold.addEventListener('click', function () {
	document.execCommand('bold');
});