JSFiddle - React, Tailwind, and code Playground

HTML

<div style="position:relative">
  <span style="position:absolute; left:7px">PN</span>
  <input max-length="4" id="field" placeholder="Mã đơn hàng" />
</div>

CSS

#field{
  text-indent:27px;
}

JavaScript

document.getElementById("field").maxLength = "4";