Google Ad’s Enhanced Conversions allows us to send hashed (encrypted) customer data to Google Ads when a purchase event or lead has been submitted (including email address, phone number and name) for them to match against Google / Gmail accounts.
It is a way to identify users across devices and improves campaign tracking because the conversion can be matched against a particular Google Account user when they saw a YouTube ad or clicked on a PPC ad while logged in.
This means that you can improve campaign tracking by supplementing conversion events with Enhanced Conversions rather than just relying on gclid / click id and UTM’s, which are prone to dropping on redirects and GDPR plugins.
Enhanced Conversions can be implemented via Gtag or Google Tag Manager and provides a combative approach to the cookie apocalypse in prevent conversion attribution being lost to the Direct Channel and making sure your paid campaigns can be optimised for performance.