"Please select category" as default value in a select list Similar to how the search box on many sites has a default value of "search", how do I give a select list a default value without making that value a valid option in the list of options. See example below:
For adding text to your input field, write a custom module and place the code in there

function yourmodule_form_alter(&amp;$form, &amp;$form_state, $form_id){
    if($form_id == "your_form"){
     $form['some_element']['#attributes']['placeholder'] = t('Select Category');
}