How can I remove iCloud data for a specific app I want to delete Pixel Gun 3D status but it is apparently saved to iCloud.

I have tried deleting the app and reinstalling but it kept the game's data.  How can completely delete and reinstall the app as new with no previous data?
As detailed in Apple's support article, 


Go to Settings > iCloud > Storage > Manage Storage (on your device)
Tap on the app's name, Pixel Gun 3D and tap "Delete Data"


This is for an iOS device, which I am assuming you are using. Mac instructions are detailed on the Apple Support article.