I'd suggest you do some investigating on the web. Most people have a tendency to recommend what IMO, nobody can tell you which is right for you unless they're completely objective, know exactly what your current/anticipated requirements are & have evaluated them all for those purposes. Some are available as standalone programs, others only as components of a Suite that includes other apps, so cost can be deceptive. Several are free, some are inexpensive, others cost more. There are at least a dozen word processing programs for Mac. but then again they differ from one anotherĪs well :-) No matter what you choose there will be a learning curve involved.
However, it is comparable but not identical in all respects to its Windows siblings. As Daniel pointed out, Microsoft Word is available for the Mac as a part of Office:mac suites but not as a standalone program.