One of the things that make people hold back from switching to a PC to a Mac is the issue of compatibility. This is not that big of an issue as it was many years ago, though. Many software developers and vendors have seen the need to create Mac-compatible products, and Microsoft is one of them. You can buy Microsoft Office for Mac in most any online or offline software store.
Alternatively, you may opt to go for Mac’s own programs. They call their ‘Word’ ‘Pages,’ while ‘Excel’ is ‘Numbers.’ The interface is very similar and truth be told, the functionality of these programs is much better than Microsoft’s anyway.