Pay Per Click
Google will also display ads that are relevant to the search query above the main body of the page and to the right of the SERP (search engine research page).
Google says that paid advertising will only appear if they complement your regular search results. The position of these ads are based on bids – how much the advertiser is willing to pay for a single click on that ad – the higher the bid the higher up the ad the web page will appear.
Each time a user clicks on these ads, the advertiser pays Google the agreed bidding price. The popularity of the advertisement also has relevance on the advertisement ranking.
The more clicks an advertisement receives, the more likely the advertisement will receive a more prominent position on the web page.
Paid search has no effect on natural or organic search results for the same website, and vice versa. Once you stop paying for advertisement, your web site stops getting listed on those premium positions.