JSFiddle - React, Tailwind, and code Playground

HTML

<div class="main_loop">    
        <div class="loop" style="display:none;">
           <input type="text" value="first name" />
           <input type="text" value="lastname" />
           <input type="text" value="mail" />
           <input type="text" value="company" />
        </div> 
    </div>

        <div class="main">
        </div>

        <button>Add person</button>

JavaScript

$('button').on('click', function () {
   if ($('.main .loop').length < 5) {
     $('.main_loop .loop').clone().appendTo(".main").show();

     $(".main .loop:nth-child("+$('.main .loop').length+")").children().each(function(){

         $(this).val($(this).val()+$('.main .loop').length);
     });
    }
});