Most PC's come with some sort of word processing application, like Word, already installed, does a Macbook Pro have one, is so, I can't find it. If not, why not, it has everything else.
For basic text processing you can use 'textedit', captainfun. You will find it in your 'Applications folder.
It is certainly not a "full blown" wordprocessor like Word or Pages , but you can actually use it to write quite substantial documents if you wish, with tables, inserted graphics, text formatting etc. It also has built in spell checking and grammar checking etc. It can save files in an extended RFT format, html or as PDFs
Your MBP will also have come with a 30day trial version of iWork, which includes the very competent "Pages" word processing/ page layout software. Many people who try it end up never going back to Word.
I personally love the iWork suite. I can't justify paying twice as much for essentially the same functionality as the Microsoft stuff. Pages and Numbers are about neck and neck with Microsoft equivalents (some better features, some worse), but Keynote totally blows Powerpoint out of the water.
You can export Microsoft compatible documents out of iWork (although some formatting may not come out as expected.)