If you'd like to work with Office 2016 download it online or buy the software from Microsoft. Learn about buying Office 2016 here.
Office 2016 for Mac is the newest version of the Office suite for Mac computers, and it's a big upgrade from previous versions, including Office for Mac 2011 and Office for Mac 2008. While Office 2016 for Mac is more similar to the Windows version than previous versions of Office for Mac, keep in mind that it doesn't include all of the features you'll find in the Windows version.
If you have a Microsoft account, you can use Office mobile apps to create and edit Office documents from various devices, including iOS, Android, and Windows Phone. The basic editing features are available for free, but you'll need an Office 365 subscription to use more advanced features like real-time co-authoring.
Keep in mind that none of the Office mobile apps include all of the features found in the desktop version. They will likely be most helpful for making minor edits when you're on the go.