Backing up to iCloud
I have a Mac (Mini) and an iPad. I purchased Microsoft Office for Macs from Microsoft (purchased not subscribed through Microsoft 365). I save all my Excel and Word files on my Mac to both Documents and iCloud Drive. When I open my Excel and Word files through iCloud.com on my iPad I see that I cannot edit or save them. There is a message saying that I cannot edit them unless I have a subscription to Microsoft 365.
So my question is: why can't I edit and save files on my iPad which I have saved to iCloud Drive on my Mac? In other words, if I have saved them to iCloud Drive why can't I edit and save them on my iPad when I am traveling?
Thank you.
iPad Air, iPadOS 17