Jama - Jama combines requirement management software with enterprise collaboration capabilities to solve product delivery problems.
Wondershare PDFelement - All-in-one PDF editor
Reqtify - Reqtify is an easy to use, interactive application for managing requirements.
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.
ReqView - Simple and powerful requirements management tool enabling easy requirements gathering, traceability tracking and offline collaboration.
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.