docassemble - docassemble is a free, open-source expert system for guided interviews and document assembly.

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.

Knackly - Generate contracts, emails, or other documents of any complexity by automating your knack for doing...

Microsoft Word - Microsoft Word is a commercial word document processor for Windows.

HotDocs - Template-driven, automated document & form assembly software

Apache OpenOffice Writer - Open-source word processor of the Apache OpenOffice suite.