A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
Online account validation and online document editing are 2 separate issues. If you are running the purchased version of Office and it's been activated, you can simply sign out of OneDrive and save files to your hard drive instead. If you are subscribing to Office 365, you can do that for a month, then you need to re-connect to maintain activation. Then you can disconnect again.
If you spend large amounts of time not connected or in remote areas, Office 365 is not the best choice. You should uninstall it and get a purchased version of Office.