Most people use Microsoft Word word processing software when they want a blank page that they can type on and print. There are lots of advantages to using Word.
But, depending on what operating system you are running - your computer may come with a different "word processing" software package. Either way, most computers come with easy-to-use programs which will provide you with a blank canvas for starting your letter or address.
Because I'm a Windows user, I know more about Microsoft Word than any of these other word processing programs - so I'll give you the lowdown on that:
The advantages of Microsoft Word
Microsoft Word allows the person writing the document to format, spellcheck, search for particular words and perform many other useful functions. Most people choose Word Microsoft to write everything from essays and articles to letters and reports. The software has a footnote provision build in, which helps when you're writing an academic document.