JSFiddle - React, Tailwind, and code Playground

HTML

<button type="button">Header!</button>

JavaScript

$(function() {
    $('button').click(function() {
        //insert your h3
        var header = $('<h3>My Header!</h3>');
        //append to wherever
        $('body').append(header);
        //set a timeout, then fade away!
        setTimeout(function() {
            header.fadeOut(300);
        }, 5000);
    });
});