JSFiddle - React, Tailwind, and code Playground

HTML

<button class="add-form">add form</button>
<form id="main-form">
    <div class="form-item row">
      <input type="text" name="abc">
    </div>
</form>
<div class="stay-hidden original-form-item">
  <input type="text" name="abc">
</div>

CSS

.stay-hidden {
    display:none;
}

JavaScript

// Add form
jQuery('.add-form').click(function() {
    // "Copy" default form
    formGroup = jQuery('.original-form-item').clone();
    // "Paste" default form
    jQuery('#main-form').append('<div class="form-item row">'+ formGroup.html() +'</div>');

});