Open Settings
Tap your name at the top
Tap iCloud
Turn off the iCloud services you want to disable
To turn off iCloud completely, tap Sign Out
Enter your Apple ID password if prompted
Choose whether to keep a copy of your data on the device
Confirm Sign Out
On Mac, open System Settings
Click your Apple ID
Click iCloud
Turn off the iCloud services you want to disable
To turn off iCloud completely, click Sign Out
Confirm Sign Out