Microsoft Office Online
Office Online is an online office suite offered by Microsoft, which allows users to create and edit files using lightweight, web browser-based versions of Microsoft Office apps: Word, Excel, PowerPoint and OneNote.
With them you’ll be able to work on text documents, spreadsheets and presentations like you do with Office. Obviously you won’t have as many tools and options as the standard Office, but on the upside, you’re able to work on your documents pretty much anywhere, at any time, as long as you have an internet connection.
Great advantage of office online is co-authoring which means on a same documents multiple people can work simultaneously. For example in a finance department multiple people work on a same office document in real-time.