The importance of On-page optimization is to obtain web pages on the top positions of search engines like Google, Yahoo, Bing etc…
On-Page Optimization is necessary to emphasize the content of the page and to concentrate on target keywords, Optimization of any web page begins with keyword selection. You need to select keywords that are related to the content of your website, have high search volume and low competition.
The purpose of optimizing each and every page on website by setting up the target keywords, which are related to that specific page and every page should explains visitors and search engines what this page is about. The final goal is to achieve top position in search results for these keywords.
On-Page SEO is done by putting the main keyword or search phrase at relevant visible and invisible (meta) page elements. The best approach is to create a nice, easily readable page where visitors will quickly find the information they are looking for.
Once you have the text written all you have to do is to create a page title which contains the target keyword, to add few header tags (h1, h2, h3, etc.) to label sections or paragraphs, to create right meta description which, of course, contains the keyword and finally, to check word frequency to avoid excessive use of particular word phrases.
The purpose of any on-page optimization is simply to explain to everybody, including search engines, what the page is about.