JSFiddle - React, Tailwind, and code Playground

HTML

<form id="quick_post" method="post"> 
    <table id="input_fields">
        <tr> 
            <td><input class="orderinput" type="text" name="product[]" /></td> 
            <td><input class="orderquan" type="text" name="quantity[]" size="1" maxlength="3" /></td>
        </tr>
    </table>
</form>

<input class="more" type="button" value="Addmore" name="addmore" />

JavaScript

$(function () {
    $('input.more').on('click', function () {
        var $table = $('#input_fields');
        var $tr = $table.find('tr').eq(0).clone();
        $tr.appendTo($table).find('input').val('');
    });
});