Google owns the internet basically. They are the #1 website in the world. Over 80% of all the worlds searches happen on google so why would you not be promoted your brand through their adwords program? You dont like money? You dont want business? Of course you do or you wouldnt be on our website.
Because google has such a massive reach the options are endless but the 5 main categories for adwords are Search, Display, Shopping, Video and Apps. These are all their main campaign types but with even more options within them.