Facebook Offline Conversion Tracking:
A fundamental challenge for businesses today is measuring the impact of their online advertising campaigns on store visits and sales. Well, Facebook’s Offline conversion tracking allows you to track when transactions occur in a physical retail store or offline channels after people see or engage with you Facebook ad.
So how does this all work?
Firstly, you need to upload offline event sets to ads manager. This includes groups of data about offline actions so that when you create an ad, you can connect an offline event set that lets you attribute actions that happen offline back to your Facebook ads. Essentially Facebook uses the offline data to match with the targeting already set up in ads manager, so that Facebook can measure the events you specify as a result of people seeing or engaging with your ads.
For the offline data to match Facebook users it is best to include as much information as possible. So for example by including an email address, phone number, city, name, postal code etc.