it would be nice if i can save the file to my pc.
Wenjun Gong (MSFT Product Team) commented
Thanks for the idea.
Do you want to download a copy to your PC? To do that, you can find the Download command from File -> Save As tab in editing mode.
So far, the auto save of Office Online will save the changes to the online document automatically when you are editing online.
Hope this helps and please keep posting more ideas!