How to add a subtitle to a NEWS (Post Page)?

Hi Guys I'm trying to add a subtitle (H2) to a NEWS which I choose as blog page. I tried to add a title on the BLOG page but apparently there are no connection since the NEWS page seem to be Theme Customization page on its own. I'm quite sure I will have to add some php but there is any easy way to do it? If not guide me through via php. Thanks