Modifying the comments form

Take a look in the themes comments.php file and you will see a line where the comments area is called in using:

<?php comment_form(); ?>

In some cases I found it was contained within a conditional like this:

if ( comments_open() ) comment_form();

You can replace it with the following code, injecting in any modifications to the fields as you need:

if ( comments_open() ) { ?>

    <?php $comment_args = array( 'title_reply'=>'Leave a reply',

        'fields' => apply_filters( 'comment_form_default_fields', array(

                'author' =>
                    '<div class="row">
                        <div class="large-4 columns comment-form-author">' .
                            '<input id="author" 
name="author" type="text" value="' . esc_attr( $commenter['comment_author'] ) .
                    '" size="30"' . $aria_req . ' placeholder="Name*" />
                        </div>',

                'email' =>
                      '<div class="large-4 columns comment-form-email">' .
                            '<input id="email" name="email" type="text" 
value="' . esc_attr(  $commenter['comment_author_email'] ) .
                    '" size="30"' . $aria_req . ' placeholder="Email*" />
                      </div>',

                'url' =>
                    '<div 
class="large-4 columns comment-form-url">' .
                            '<input id="url" name="url" type="text" value="' . esc_attr( $commenter['comment_author_url'] ) .
                    '" size="30" 
placeholder="Website" />
                    </div>
                </div>', )
        ),

        'comment_field' => '<div>' .

            '<textarea id="comment" name="comment" cols="45" rows="8" aria-required="true" placeholder="Comment*" 
></textarea>' .

            '</div>',

        'comment_notes_after' => '',

    );

    comment_form($comment_args); ?>


<?php } ?>