For seo, h1 - h6 tags, can they have id, class where to read it?

Question

Search Engine Optimization

When laying out a site, you can set classes for h1 - h6 tags, and how this affects search engine optimization, I did not find a single specific article, maybe I was looking badly. Thank you.

Answer 1

Can. Doesn't affect at all. If it still had an influence, then the book "Legends and Tales of Google" would be five times thicker.
What matters is only their presence, number, position in the dom and, of course, the content.
And classes and id can be molded at your own discretion.