Google Chromebooks are - in general - low-priced laptops which you're probably considering alongside cheap laptops running Windows.
In the past, we'd have said that they were very different devices, but these days Chromebooks can run Android apps as well as Chrome web apps. This means there's a huge choice of software you can install and run, often without an internet connection.
For a very long time Microsoft Office wasn't available on Chromebooks, but recently it has been released for all Chromebooks that have the Google Play store (not all have it, so check before you buy).
For some people, Office is a deal-maker, but for a lot of people the obvious alternative on the Chromebook is to use Google apps instead.
Docs is the equivalent of Word, Sheets replaces Excel and Slides PowerPoint. Each of these is compatible with most Microsoft Office files, and they provide most of the core functions you're likely to need.
Better still, Google's apps allow real-time collaboration on a file so you can work on it at the same time as others, and all for free: no Office 365 subscription required.
We give a lot more in-depth advice on buying a Chromebook with a list of the best models to buy, and you can check out Google's site which explains which apps you can use on a Chromebook to replace those you might use on a PC or Mac.
There are still a few limitations to be aware of, such as the fact you can't install iTunes and sync (or back up) an iPhone or iPad. But since those devices can now back themselves up directly to iCloud, there's rarely a need to connect them to a computer.