Reply To: How to fix header.php for better SEO?

Frontier already has an H1 tag, the Site Title. But it looks like you disabled it.
Go to Frontier Options -> Display -> Top Bar

Enable Site Title (which has the H1 tag) and disable Site Description.

You can then control what is displayed on the title by using this filter. Add this code on a child-theme functions.php

function frontier_top_bar_title_text() {
   return 'Malware Removal & Advanced PC Protection';
}
add_filter( 'frontier_top_bar_title', 'frontier_top_bar_title_text' );

If you need even more control then you can disable both Title and Description and use the action “frontier_before_top_bar” where you can output anything you want.