Website optimization or SEO (Search Engine Optimization) is a set of actions during which your website is displayed in a suitable position (example on the first page) in the search results of a keyword or phrase in search engines.
You do not pay to be displayed on the first page, your website is placed on that first page naturally (organic).
When you optimize your website, for example, being on the first page of search results, this result is relatively stable. This means that you maintain this position for at least several months. This period depends on the website activity and the competitor's activity, directly related to your brand's visibility in the target community.