I used Microsoft Office for years, and it worked well for me. Microsoft Office includes Word (the word processor), Excel (a spreadsheet program), and PowerPoint (a presentation program). Microsoft also bundles in other programs with the different versions of Microsoft Office. Microsoft Office is ridiculously expensive, but I didn't mind as long as my employer paid for it. That "free ride" ended a few years ago when I left that company and found myself paying for my own software. I started looking for alternatives. I found several.
OpenOffice (now called Apache OpenOffice) is one of the more popular options. It includes a word processor, spreadsheet, presentation program, and more. It is very powerful although it does not have all the capabilities of the Microsoft products. Still, I found that it always had everything I needed and a lot more that I never used. I find OpenOffice to be much easier to use than the Microsoft products. I also fell in love with the price tag: free.
Apache OpenOffice has been upgraded several times over the years. Each new upgrade brings additional capabilities. About three years ago, many of the programmers who had developed OpenOffice left the project and started a new, competitive product called LibreOffice. I switched to LibreOffice soon after and have stayed with it. (See my article about that at http://goo.gl/9lCL8Z.) However, OpenOffice attracted new programmers, and the product has continued to be developed and improved. Now those programmers have released a significant update: version 4.
Most of the improvements in Apache OpenOffice 4.0 are incremental, not radical changes. However, there are many such improvements. The result is a better product that is now approaching all the capabilities of the Microsoft products. I won't list all the changes here as there are so many of them and also because you can already find that list at http://sourceforge.net/projects/openofficeorg.mirror/.
If you are interested in obtaining a FREE, powerful, and easy-to-use suite of office programs for your Windows, Macintosh, or Linux system, you might look at OpenOffice at http://www.openoffice.org/. I think you will like it.
All this raises the question, "Which is better: OpenOffice or LibreOffice?" All I can say is that both are excellent products and both are available free of charge. In fact, the two programs are very similar. These free programs include all available features and there are no "beg screens" that ask for money. In fact, there is no way to pay for them, the complete programs are free to everyone for personal and business uses alike. For most people, I think the answer to the question is, "It depends on your personal preferences." Since I am already using LibreOffice and am comfortable with it, I will remain with LibreOffice (available at https://www.libreoffice.org/) and I am using it to write this article. However, if LibreOffice was not available, I could be very happy with Apache OpenOffice at http://www.openoffice.org/. Both products meet all my needs, and I suspect they meet the needs of most home users. They may or may not meet the needs of corporations.
Both programs have millions of satisfied users around the world. I don't think you will go wrong with either one.