There are dozens of document scanning apps for IOS but you have to stand up and take notice when document management titan Evernote jumps in. I have been testing it for months and it works really well. 

If you have a ScanSnap Evernote edition, you can even control it from the App ( but the app takes scans using your smartphone camera). I tested it with receipts, documents and cards. The app did almost perfect automatic improvements every time. 

Download it from iTunes (link)