Word Processor :
A word processor is a computer application device.It is used for composition, editing, formatting and printing of printable material. The term word processing was coined by IBM in the late 1960s. At that time it was used to dictate machines and ordinary manually operated typewriters. Word processing tools have actually descended from being text formatting tools.These often times known as the text justification tools. The earlier word processors used tag based mark ups for document formatting, the recent ones use graphical user interface.
Microsoft word is the most commonly used computer word processing system.
Typical functions of a word processor are checking spellings, grammar, footnote numbering, page numbering,making indices of keywords and their page numbers, preparing tables of content with section titles on them and their page numbers, etc.
Free word processor:
Free or open source word processors are gradually becoming popular due to the usefulness being widespread.These can be downloaded from the internet. Other popular open source applications are KWord, LyX, Open Office.org Writer are rapidly gaining in popularity. Besides these, word processors such as Google Docs are a relatively new category. Some other popular free word processors are:

• Jarte Word Processor: The free version of this software is used for supporting Microsoft Word documents, Rich Text format documents (RTF) and plain text documents(ASCII). It comes with windows. It is designed to work on windows only.
• Abi Word: This word processor has been made for supporting Microsoft Word documents, Open Office documents, Word Perfect documents, HTML web pages, Rich Text Format documents etc. The platforms supported are Windows, Linux, FreeBSD.
• Yeah Write for Windows: This runs only on windows. It has an unusual approach towards creating documents. It has a fill- in- the blanks interfaceIt saves files automatically , does not need the user to know the names of the files.
• Writely ,this is a free word processor launched by Google to edit blogs,to save outputs to a post rather than in files.It does much of the functions of MS word saves the outputs into PDF formats.It is also used for collaborative editting.