How to delete activity data?

Go to Activities widget in the watch and finds all activities history➡tap the activity you want to delete ➡ swipe left and click Delete button

Delete from Amazfit App: 

Amazfit App➡ Workout/Status➡Click See more exercises ➡press and hold the activity you want to delete till the dialog Delete this record pop up➡ click OK button to delete it.

Note: Once the data in the App is deleted, there is no way to retrieve it from the Cloud or anywhere.