Every day, consumers search for specific terms or phrases, and Google will show the consumer relevant ads based on the keywords used in the search. Simple enough. Websites that want their ads to surface toward the top on the results page bid on keywords that they believe people will use when looking for their type of business. For example, an electrician located in Milwaukee might bid on the keywords “electrician Milwaukee,” “electrician,” or “broken outlet plug.”
Depending on how much you bid compared to other electricians in the designated area, your ad may show up on the results page when people search for those specific terms on which you bid. In addition to how much you bid (the cost), Google also takes into account the relevance and quality of your ad and the quality of your website pages. Even bidders with the highest investment per click won't show up if the terms don't match perfectly - 'flower store Milwaukee.'