Whenever people who are trying to collaborate on projects use operating systems made by different companies, there are always going to be some problems; you're often forced to use different applications and that means that the files that you create on one operating system may be in a format that can't be easily opened on the other. The most common example is the .docx format, which is widely used, but not easy to manage on a Mac without MS Office installed.
So, if you don't have Microsoft Office and most importantly Microsoft Word installed on your Mac, there are a couple of easy ways for you to open a .docx file. In case all you want to do is to read the content and you're not too worried about the text formatting, the simplest solution is to use TextEdit - an application that's installed by default on Macs. So, what you want to do is to open your Application folder, then run TextEdit and open the .docx file from the application. Alternatively, you can drag the .docx document into TextEdit's window in case that seems quicker for you. On my Mac, .docx files were set to automatically open using TextEdit, but I've seen devices where that wasn't the case. TextEdit will also allow you to edit the document, but it will completely mess up the formatting, so if you want to do that, I recommend using the next option.
Another simple solution that you can use to view and edit .docx files without actually installing any additional software is the Pages application. Unlike the previously mentioned tool, this one does a lot better at keeping the document's original formatting, even when you're dealing with more complicated stuff. To open a .docx file in Pages, you can either drag it into the application's window or right-click the file, go to the Open With menu and select Pages. When you're finished editing the document, all you have to do is go to File, then hover your mouse over the Export To section and select Word. From the menu that opens up you can even select to save the file in the .doc format, in case one of your collaborators uses an older version of Word, that can't deal with .docx files.
However, if you're often forced into situations where you have to collaborate with Windows users, the least painful solution would be to install Microsoft Office. In case you're not willing to spend money on the suite, there are quite a few third-party text editors that work across multiple platforms such as Google Docs or Open Office and that won't cost you anything.
Now that you've learned how to open .docx files on your Mac, you may also want to check out some of our other interesting articles such as: "Best tools to keep your Mac organized", "10 +1 Useful Mac keyboard shortcuts that you should know", "Free Alternatives to Acrobat Reader for Mac".