These are the Header Tags, all of us know that google doesn't count meta tags at the time of crawling. but google crawlers looks into header tags. there are 6 types of header tags starting from h1 to h6. google bot checks whether the headings are relavant to the content and bring your site in SERP's as well.
H1 best to mirror the title tag; Hx separated with a paragraph = Good start for on-page optimization. Some search engines place significant importance on H tags, because their assumption is that a "true" heading means that all the paragraphs up until the next heading will be about that particular subject. This idea goes back to Information Science and HTML's parent language, SGML. So you can see why the academic minds who design search engines might value a word in an H tag very highly. H1 and H2 tags are analyzed from two perspectives: from the point of view of search engines and Internet surfers.
Headers is like the chapters of a book while title is like the book title. Technically, you will want to have a few H1, H2 and H3 tags in a page so that Search Engines can allocate you a better relevancy.
h1 and h2 tags are tags for heading .. you can practices in any html editor writing it in the code <h1>SEO Services</h1> when you check preview the text will be bold and visible .. this tags used to have importance for on page optimization now it's value is less then it was used to be
In onpage point of view H1 and H2 tags are very imporatant. H1 and H2 tags should contain your targeted keywords. It helps in getting ranking in search engine. also seo friendly.
All of that and more is contained right here, in my X/HTML Coding Best Practices Guide: http://forums.digitalpoint.com/showthread.php?p=8141503 Uhm, not that I mean to be a semantic nit-pick but headers are sent by the Web server. These tags are HEADINGS. Huge difference.
H1 and H2 basically used for Title and subtitle. please be sure not to use many h1 tags in a single page