JSFiddle - React, Tailwind, and code Playground

HTML

<form action="..." method="post" class="feed">
    <div class="datetime">
        Select on what date to add:<br />
        <input type="radio" name="dateType" id="dtNow" value="now" checked />
        <label for="dtNow">Now</label><br />
        
        <input type="radio" name="dateType" id="dtSel" value="pickadate" />
        <label for="dtSel">Or pick a date:</label><br />
        <div>
            Date and time selector
        </div>
    </div>
</form>

JavaScript

$(function() {
    $('.datetime div').hide();

    $('.datetime [type=radio]').on('change', function() {
        $('.datetime div').toggle( $('.datetime [type=radio]:checked').val() == 'pickadate');

    });
});