var h = document.getElementById("myH2");
h.insertAdjacentHTML("afterend", "<p>My new paragraph</p>");
<script src="script.js"></script>
let target = document.getElementById("ID");
target.innerHTML += "<p>CONTENTS</p>";
<script src ="path/your js file name"></script>
document.getElementById('tag-id').innerHTML = '<ol><li>html data</li></ol>';
$(document).ready(function() {
// add your code here
})