Google AdWords is the platform in which business owners and advertisers can pay to advertise their products or services. Their ads show up on Google search results and/or on Google partner sites.
Google AdSense is the platform in which website publishers can be paid to display ads on their websites, by being a part of the Google ad network. Google acts as a middleman between advertisers using AdWords to buy advertising and publishers using AdSense to display the advertising to visitors.
To be simple Google Adwords allows you to display ads on SERP where as Google Adsense is displaying Google's ads on your website. for Google adwords you have to pay and for Google Adsense you will be paid for displaying ads.