For option buttons, when we click on labels, the option buttons should be selected. In order to achieve this, We need to put input inside labels. For example instead of write this: <input class="w3-check" type="checkbox" checked="checked"> <label>Milk</label> We should write this: <label> <input class="w3-check" type="checkbox" checked="checked"> Milk</label> Now when we click on CheckBox's label the checkbox gets checked. This is the same for option button. We can change this in html tutorials and w3.css tutorials too. like here. Again thanks a lot for fantastic website. I've learned everything about web, First from W3Schools. Chears.