Add additional field to header

I am trying to add another header field of a phone number. I added it to the function catchbox_header_details: <h1 id="site-title">" title="<?php echo esc_attr( get_bloginfo( 'name', 'display' ) ); ?>" rel="home"><?php bloginfo( 'name' ); ?></h1> <h2 id="site-description"><?php bloginfo( 'description' ); ?></h2> <h2 id="site-phone">Phone: (XXX) XXX-XXXX</h2> </div><!-- #hgroup --> which appears to display fine on all devices. Although on an iPhone, it appears there is a completely different render with the menu being above the site title and the additional information is not displayed. Where can I edit the iPhone header contents?