To disconnect an iPhone from an iPad, you can use iTunes, the devices themselves, or disable Handoff, the feature connecting them through Apple ID.

To remove your Apple ID from an iPad, you'll need to go into your Settings app and navigate through your Apple ID menus, or use iCloud's website.

The quickest way is to sign out of your Apple ID/Apple Account on the iPad in Settings You can disconnect your iPad from your iPhone by signing out of your Apple ID/Apple Account on your iPad.