<form action="/action_page.php">
<label for="cars">Choose a car:</label>
<select name="cars" id="cars" multiple>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="opel">Opel</option>
<option value="audi">Audi</option>
</select>
<br><br>
<input type="submit" value="Submit">
</form>