JSFiddle - React, Tailwind, and code Playground

HTML

<div><input type="text" placeholder="existing"/></div>
<button class="add">add</button>

JavaScript

var add = document.querySelector(".add");
var div = document.querySelector("div");

add.addEventListener('click', function () {
    console.log(div.innerHTML);
    var input = document.createElement('input')
    input.type = "text";
    input.placeholder = "new";
    div.appendChild(input);

});