The header, section, article and aside tags must contain the heading, and if so, is it obligatory h1?

Question

HTML

Good afternoon. Do the header, section, article, and aside tags have to contain a title? and if so, is h1 required?
Html5 tags can be used for styling? Or is it necessary to wrap the content in a div and apply styles to this div?
apart from the fact that main cannot be nested in article,footer,header,aside,nav are there any other restrictions on tag nesting? For example, would it be correct to wrap all the content in a div and create a header, main , footer inside it?
The h1 heading must be the only one and must it be located in the header ?
And is it true that these tags do not affect SEO in any way and are useful only for all sorts of readers? I’m not too lazy to read, it’s just that the information on each resource is different, I’m already confused. And to read off the documentation knowledge of English is not enough.

Answer 1

Tags h1,h2, etc. are used for the logical structure of the text. You can compare it to a book. h1 is the title of the book, it is one and comes at the very beginning. Accordingly, the h1 tag should be alone on the page and is above all other h tags. Tags should be in order.
H tags cannot be used for styling, this is a common mistake of layout designers.
Influence, enter keywords in them. h1 is not recommended to be the same as title.

Answer 2

Here's what the w3c validator outputs (if section has no heading): The section is missing a heading. Consider using h2-, h6 elements. That is, h2 calls with a head - but look at the logic on the site.

Answer 3

you can do this: section>header>h1
you can do this: section>h1
link - http://htmlbook.ru/html/section