PPC stands for Pay-Per-Click. Google Ads is a type of PPC service. Facebook and other platforms also offer PPC marketing; Google Ads are just a different flavor!
The difference between Google Ads VS Social Media Ads is that on Google, there is a search taking place for that specific item. Social Ads try to disrupt people into making a purchase; with Google Ads, the user is searching for the thing that you provide online. It’s often a much more powerful tactic to run Google Ads, depending on your business type.