A:Answer Hello,
Google Docs is a part of the Chromebook and it's operating system. It is a Google made product and operating system. Since it is mainly a web-based (OS) operating system, you are using and changing your documents in an online system. However, you can have Google Docs save and edit offline too if you set it up that way.
You are not limited to Google Docs though. If you have a subscription to say, Microsoft's Office 365, you can use that as well to do your Word documents, Excel Spreadsheets, etc.
Basically, anything that you can edit online, you can use on your Chromebook. The main difference between it and any Windows or Mac based computer is that the Chrome OS runs and updates online. The hard drive is smaller, so you can save documents, pictures, etc. on it, but it is based on an online model, where everything you do they want you to utilize the Internet and it's cloud systems, especially Google Docs, Google Drive, etc.
I hope that helps you out!