Search engine optimisation (SEO) is the process of using different strategies to make a website more visible in search engines. The purpose of SEO is to improve your site's ranking, indicating that it contains valuable content which searchers are looking for. Higher-ranking sites are typically those that are linked to many other sites, giving them much greater visibility.
SEO uses certain strategies and techniques to achieve its goal. It can be broken down into several subcategories, including link building, on-page search engine optimisation (which involves making changes directly to the site itself), and off-page factors such as social media signals and citations. SEO has changed tremendously over time because of Google's regular updates, but it remains an important part of online marketing.