Open Settings
Tap your name
Tap iCloud
Turn off the apps you do not want syncing
Tap iCloud Backup
Turn off iCloud Backup
Tap Find My
Turn off Find My iPhone
Enter your Apple ID password if prompted
Tap Sign Out at the bottom of the Apple ID screen
Choose whether to keep a copy of your data on the device
Confirm Sign Out
On a Mac, open System Settings
Click your Apple ID
Click iCloud
Turn off the services you do not want syncing
Click Sign Out
Confirm Sign Out
If needed, delete iCloud data from iCloud.com
If needed, remove the device from your Apple ID account
If needed, disable iCloud on other Apple devices using the same Apple ID