Change H2 Tags To H3 Tags On Default Layout Page

We have two H1 tags and thirteen H2 tags on our home page and several on our layout default page. We understand that Google would like one H1 tag on a product page and no more than three H2 tags for good SEO optimization. Since the layout of our default page is on every page, we would like to know how to change the H2 tags to H3 or higher so we can have better Search Engine Optimization.
Thank you very much,
Jerry Howard

Looks like you wrote about block headers. They are displayed through wrappers, which are located in the following directory:


Change the required tags and do not forget to clear cache