<fieldset>
    <legend>Party settings</legend>

    <div>
        <label for="party-time">Date/time:</label>
        <input type="datetime-local" id="party-time"
               name="party-time" value="2018-06-12T19:30"
               min="2018-06-07T00:00" max="2018-06-14T00:00" />
    </div>

    <label for="dress-code">Dress code:</label>
    <select id="dress-code">
        <option value="fancy">Fancy</option>
        <option value="casual">Casual</option>
        <option value="pirate">Pirate</option>
    </select>

</fieldset>

Output