Header,footer,nav, article, section,aside

Question

I couldnt understand the uses of this tags
For ex :for header we can directly use <h1> tag

Answer 1

Search Engine Optimization, means getting to top searched result.
Screen reader is accessibility tools, helping people not good at eyes.
Quote :
Some of the benefits from writing semantic markup are as follows:
Search engines will consider its contents as important keywords to influence the page's search rankings (see SEO)
Screen readers can use it as a signpost to help visually impaired users navigate a page
Finding blocks of meaningful code is significantly easier than searching though endless divs with or without semantic or namespaced classes
Suggests to the developer the type of data that will be populated
Semantic naming mirrors proper custom element/component naming
https://developer.mozilla.org/en-US/docs/Glossary/Semantics

Answer 2

These are semantic tags for SEO and screen readers.
It is good practice to use them.

Answer 3

Gordon What is SEO and screen reader?