While desktop software can't be installed on Chromebooks, there are two ways to edit Microsoft Office files. You can open files in their corresponding Google productivity apps: Docs for Word files; Sheets for Excel files; or Slides for PowerPoint files. Alternatively, you can use a free Microsoft account to log into Office.com and use the web versions of Microsoft Word, Excel, PowerPoint, OneNote, or Teams.
If you just need to quickly type and save a document, try using the "Word" web app in the bottom task bar. You can create and download a new document without having to log into any account.