With Word for the web running in your web browser, you can:
Create documents to add and format text, images, and page layouts.
Get to your documents from your computer, tablet, or phone.
Share and work with others, wherever they are.
Rename a document
Select the title at the top and type a name.
Your changes are saved automatically in Word for the web.
Note: If you can’t edit the name, you might be in Reading View. Select Edit Document > Edit in Browser.