Turn on autosave

1. Toggle the AutoSave switch.

   

2. If the document isn't currently saved to OneDrive or a SharePoint library, you'll be prompted to choose a location.

Note: If you're toggling AutoSave every time you open a document, even when it's stored online, you can change the default. Go to File > Options > Save, and select or clear AutoSave OneDrive and SharePoint Online files by default on Word.