I can't upgrade my OS until I change my icloud drives settings
Apple provides free support for basic use of the Mac App Store and basic iCloud support, so I would start with them.


https://support.apple.com/en-us/HT201541
https://support.apple.com/icloud


Once you have some expert help on narrowing down what specifically you need to change / opt in / enable on your iCloud / Apple ID - then you will be able to see what / why you can't use the Mac App Store to download a new update. You probably have a few bridges to cross so try to pick apart specific messages and error conditions or specific things you can't find online if you ask a follow on question here.