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
Get access to data on 6,033,363 websites that are Google Conversion Tracking Customers. We know of 1,500,120 live websites using Google Conversion Tracking and an additional 4,533,243 sites that used Google Conversion Tracking historically and 736,604 websites in the United States.
Get a list of 6,033,363 websites using Google Conversion Tracking which includes location information, hosting data, contact details, 1,500,120 currently live websites and an additional 6,642,991 domains that redirect to sites in this list. 4,533,243 sites that used this technology previously and 736,604 websites in the United States currently using Google Conversion Tracking.