Adventure Sync is a feature in Pokemon Go that lets you track steps and earn rewards without opening the app. The feature was added to the game in late 2018 with the version 1.93. 1 update and does not require an in-app purchase to use.
How to Enable Adventure Sync in Pokemon Go (Full Guide)
Pokemon Go's Adventure Sync connects to built-in Apple Health on iPhone and Google Fit on Android. These services, once enabled, essentially turn a mobile device into a pedometer, capable of tracking the number of steps taken and distance traveled.
This data is then synced to the Pokemon Go app and the extra activity is added to your game file.
Open the Pokemon Go app on your smartphone.
