JSFiddle - React, Tailwind, and code Playground
HTML
<form action="form_sent.php" method="post">
<input name="name" type="text" placeholder="Name"><br>
<input name="phone" type="text" placeholder="Phone"><br>
<input name="email" type="text" placeholder="E-Mail"><br><br>
<button>Add more fields</button><br><br>
<input type="submit">
</form>