JSFiddle - React, Tailwind, and code Playground

HTML

<div>
  <input type="text" />
  <span><button class="generate">Izmeni</button></span>
</div>
<div>
  <input type="text" />
  <span><button class="generate">Izmeni</button></span>
</div>
<div>
  <input type="text" />
  <span><button class="generate">Izmeni</button></span>
</div>

JavaScript

$(".generate").click(function()	{
	var chars = "0123456789";
  var string_length = 13;
  var randomstring = '';
  for (var i=0; i<string_length; i++) {
    var rnum = Math.floor(Math.random() * chars.length);
    randomstring += chars.substring(rnum, rnum+1);
  }
  $(this).parent().prev().val(randomstring);    
});