Via local app

When opening a previously saved document:

If the AutoSave button is set to off – this means the document is on the trust server

To save any changes made to the document:

                                       

Note –  AutoSave set as off, doesn’t disable the default AutoSave on setting in the web based Cloud

If the AutoSave button is set to on – this means you have OneDrive 


Via Portal

When opening a previously saved document, AutoSave by default is set to on.