This free tool in AdWords can show you what happens after customers click your ad (for example, whether they purchased your product, called from a mobile phone or downloaded your app).
https://support.google.com/adwords/answer/1722054
Analytics and Tracking · Conversion Optimization · Conversion Tracking
Get access to data on 6,667,289 websites that are Google Conversion Tracking Customers. We know of 2,258,359 live websites using Google Conversion Tracking and an additional 4,408,930 sites that used Google Conversion Tracking historically and 1,043,427 websites in the United States.
Google Conversion Tracking websites that are also using other technologies.
Get a list of 6,667,289 websites using Google Conversion Tracking which includes location information, hosting data, contact details, 2,258,359 currently live websites and an additional 3,518,356 domains that redirect to sites in this list. 4,408,930 sites that used this technology previously and 1,043,427 websites in the United States currently using Google Conversion Tracking.