Ad words is a program by the search engines that is used by the business and brand, to position their websites at the prime locations on the SERP. Ad words are thus a paid technique to position your website on the result page.
Ad words is an important marketing tool these days as far as online marketing is considered. This is so because ad words generate large traffic to your website through relevant clicks, thus a opening up larger chances for business, through minimum investment and a little work in drafting the right content and keyword.