LibreOffice - Writer - Open-source cross-platform word processor.
HotDocs - Template-driven, automated document & form assembly software
Microsoft Word - Microsoft Word is a commercial word document processor for Windows.
WebMerge - WebMerge is an online platform that allows you to easily collect data, populate a document and send it to any contact automatically.
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.
Carbone - Generate and convert any document efficiently