Heading tags in Seo Onpage ?

[hoangvu]

I have read the Google SEO guidelines said that in SEO content, begining with H2 tag and end with H4 tag(Do not use the H1 and H5 tag from the tags)
But there are some other materials that H1 tags are extremely important and should include keywords in the H1 tag.
so which tags is better? H1 or H2 ?

 

[todion]

H1 tags is important as compared to h2, h3… because h1 tags is main sub title tag of website and defined website theme and adding main services or product headline in h1 tags.