JSFiddle - React, Tailwind, and code Playground

HTML

<form action="" method="get" id="hidden-element-test">
      First name: <input type="text" name="fname"><br>
      Last name: <input type="text" name="lname"><br>
      <input type="submit" value="Submit">
</form> 
    <br><br>   
    <button id="add-input">Add hidden input</button>
    <button id="add-textarea">Add hidden textarea</button>

JavaScript

$(document).ready(function(){
        
    $("#add-input").on('click', function(){
        $('#hidden-element-test').prepend('<input type="hidden" name="ipaddress" value="192.168.1.201" />');
        alert('Hideen Input Added.');
    });
    
    $("#add-textarea").on('click', function(){
        $('#hidden-element-test').prepend('<textarea name="instructions" style="display:none;">this is a test textarea</textarea>');
        alert('Hideen Textarea Added.');
    });
    
});