Hey there! Hello!
The exclusive file type for Microsoft Word documents is .docx. You can see the attachment showing all the information you need to know about the example Word document I created. As long as you are using Word, the file type will be the same no matter what type of computer you're on or what it's running, so you don't need to worry about it being different for me on Mac than it might be for you on Windows.
Hope this helped you out! Feel free to ask me any additional questions you may have. :-)