Title on main page

How to make this title: https://www.dropbox.com/s/1dfv2agmd5td313/4.png?dl=0 (on mane page) an <H1> tag?

You have to edit GK NSP plugin to change it. (but in this case all titles will be h1 instead of h3). If you want, you can change it in wp-content/plugins/gk-nsp/data_sources/wp/layout-parts.php file and art_title function (use h1 instead of h3).