In iOS 9, where is the "Usage" function in Settings? In iOS8's Settings page, I used to be able to go to "General" then "Usage" and it would tell me how much free space is available on the device, and how much space each app uses.

Where is this now in iOS9?
It has moved to a little different location. To access the same screen, go to: Settings > General > Storage &amp; iCloud Usage > Manage Storage

Moreover, iOS9 now has a search function inside "Settings". A user can search for a term, such as "Usage" in the search bar to access the corresponding settings.