The greatest level of information on a page is identified by this HTML tag. Page headings and headlines are the largest pieces of text on a page, and they are frequently designated with H1 tags. H1 elements can be linked to certain CSS styles or formatting to ensure that headlines are always displayed in the same font, colour, and size. H1s are vital for search engine optimization (SEO) and help indexing information easier. When anything is in an H1 tag, search engines recognise that it is significant.