On iPad, open Settings
Tap your Apple ID name at the top
Tap iCloud
Turn off the apps you do not want syncing
Tap Photos and turn off iCloud Photos if needed
Tap Messages and turn off Messages in iCloud if needed
Tap iCloud Drive and turn it off if needed
Tap Find My and review sharing settings if needed
On iPhone, open Settings
Tap your Apple ID name
Tap iCloud
Turn off the same sync options you want to stop sharing
On iPad, open Settings
Tap Messages
Turn off iMessage if you do not want texts syncing
On iPad, open Settings
Tap FaceTime
Turn off FaceTime if needed
On iPad, open Settings
Tap your Apple ID name
Scroll down and tap Sign Out to fully disconnect the iPad from the Apple ID
If you want to keep the same Apple ID but stop app syncing, disable Handoff on both devices
On iPhone, open Settings
Tap General
Tap AirPlay & Continuity
Turn off Handoff
On iPad, open Settings
Tap General
Tap AirPlay & Continuity
Turn off Handoff
To stop call and text sharing, on iPhone open Settings
Tap Phone
Tap Calls on Other Devices and turn it off
On iPad, open Settings
Tap FaceTime
Turn off Calls from iPhone if shown
To stop shared app purchases, open Settings on iPad
Tap your Apple ID name
Tap Media & Purchases
Review shared purchase settings
To remove the iPad from your Apple ID entirely, use a browser and sign in to Apple ID account page
Remove the iPad from your devices list
If using Family Sharing, remove the iPad from the family group if needed