What tags can be used in h1-h6 tag titles without harming SEO?

Question

HTML

Good afternoon, dear Optimization Gurus.
Do you think it is possible to frame individual words in the headings with a tag ? A few words in tags , like mine? What about other tags: etc.? <span>
<span>

<a>, <br>

Answer 1

You can use any inline, although it is better not to abuse it.

Answer 2

The main thing is to keep the semantics. And then there will be no harm for SEO