Change Posts Titles from h3 to h2 in Grid View

Hey faroestudio,
Try adding this code to the end of your child theme functions.php file in Appearance ▸ Editor:

function change_posts_titles_from_h3_to_h2_in_grid_view() { ?>
  <script>
(function($) {
  $(function() {
    function replaceElementTag(targetSelector, newTagString) {
      $(targetSelector).each(function(){
        var newElem = $(newTagString, {html: $(this).html()});
        $.each(this.attributes, function() {
          newElem.attr(this.name, this.value);
        });
        $(this).replaceWith(newElem);
      });
    }
    replaceElementTag('.slide-entry-wrap h3.slide-entry-title.entry-title ', '<h2></h2>');
  });
}(jQuery));
</script>
  <?php
}
add_action( 'wp_footer', 'change_posts_titles_from_h3_to_h2_in_grid_view', 99 );

If you are not using a child theme you could use the WP Code plugin then add a new snippet, in the top right corner use the PHP snippet as the code type:

and ensure that it is activated, then add the above code and save.

Best regards,
Mike