It depends upon the type of business one is looking to promote, the platform a business is ready to leverage and the end goal one wants to achieve. So some of the KPIs to consider after the  PPC Companies take campaign live, are CPC (Cost per click), CPL (Cost Per Lead), CPA ( Cost Per Acquisition), and conversion rate. These KPIs help to measure the performance of paid marketing campaigns, and list out the insights to improve further performance at a minimal cost.