How to remove your iCloud account from any device
Login to icloud.com
Go to iCloud.com and login with your Apple ID and password. If you do not know this, please contact Apple for support.
Click on "Find iPhone"
Find the green circular radar icon which says “Find My”, it will say iPhone even if you have an iPad.
Click "All Devices"
Once loaded, click on the “All Devices” dropdown. This will show all devices connected to your iCloud account, this may be one or many. Click on the device you wish to remove.
Remove Device
Once you have clicked on the device, you will see the specific device on the left-hand side of the page. Click remove from account.
Click on Remove
When the box pops up, click on “Remove”. Once loaded your iCloud has been removed from the device.
Device Successfully Removed
Once the device has been successfully removed from the account It will no longer be listed as a device on the account and if there are no other devices of the account you will see no devices listed.