iCloud app
Is there an iCloud app for my iPhone 6?
MacBook Pro, Mac OS X (10.7.4)
What is it that you are wanting to do? Most iCloud functionality is built in to iOS on your iPhone.
If you are looking for an iCloud Drive app, that is coming with iOS 9 (but you can access iCloud Drive files now from apps compatible with the files stored). http://www.macworld.com/article/2946573/hands-on-with-icloud-drive-a-new-app-in- the-ios-9-public-beta.html