The Onpage optimization refers to all measures that can be taken directly within the website in order to improve its position in the search rankings. Examples of this include measures to optimize the content or improve the meta description and title tags.

On-page optimization refers to the tweaking of a webpage for it to have a better ranking in search engine results. Optimization is defined as the modification of a computer program or a system to achieve maximum efficiency. This is what optimization is about, creating a huge use of websites for people. The most common techniques of on-page optimization are page title, images and alt tags, content, linking and Meta description. Page title is important in optimization. This is because the title is the one appearing on the top of the browser and is used by search engines in producing their search engine results.

Thank you @gaurav.solanki for the information.