Wondershare PDFelement - All-in-one PDF editor
Docr - Docr is a free app for the iPhone smartphones that lets its users scan all of their documents into sharp images and, in the end, store them as PDF files.
Foxit PhantomPDF - Edit PDF files with our feature-rich PDF Editor. Download Foxit PDF Editor to convert, sign, scan / OCR & more. A speedy PDF Editor alternative to Adobe Acrobat.
Scanner Pro - Scanner Pro turns your iPhone into portable scanner in your pocket.
Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.
Scanbot - Scanbot is a mobile app that allows you to use your device's camera as a document scanner. The app is capable of scanning a large number of source materials, and it can handle QR codes as well.