Google AdWords is an online advertising service that enables advertisers to compete to display brief advertising copy to web users, based in part on keywords, predefined by the advertisers, that might link the copy to the content of web pages shown to users.
Let's say someone conducts a Google search for products or services related to your business while you're advertising with AdWords, Google's online advertising platform.
The green section in the image on the left can contain AdWords ads. Ads can appear on the top or bottom of the Google search results page next to or under an "Ads" label. Ads are ranked primarily based on how relevant and useful they are to what the person searched for, your bid, and a few other factors.
The white section below in the said image is made up of "organic" search results. These are unpaid links to websites with content related directly to what the person searched for. The more relevant the site is to the search term, the higher the link will appear in the list. Your related website could appear here, but your ad won't.