PHP file for front page blog posts listing

Hi, Quick question to answer (I hope), which PHP file do I need to copy into & edit in my Child Theme to change the H1 tags in the blog post titles? I only want 1 * H1 tag in the front page, the Site Title. BTW: I've managed to edit my Child Theme so that the H1 tag is only applied to the Site Title on the home page - thanks for your help ;) Regards, Robertf