If you look at a search engine results page (SERP) carefully, you can generally distinguish between search results that are regular algorithmic or "organic" search listings and PPC search results which are actually paid advertisements. The latter are generally listed under the headings "sponsored results" or "featured listings" and consist of specially designed text, image or video ads that are triggered to display when your target keywords are used in a search query. The PPC ads generally appear on the right hand side and/or at the top of the search results pages.
To appear in the PPC results, advertisers sign up for the PPC program of their choice and create short text ads, image ads or videos describing the product or service available on their site in a way that will best entice searchers to visit it. During the program setup, an advertiser will decide which trigger keywords/phrases they wish to bid on and how much they are willing to pay when a visitor clicks on their ad. Generally, the higher the bid, the more likely their ad will show above their competitor's.