This article explains how to turn off iCloud on your iPhone. The instructions apply to all iOS devices. These instructions apply to devices with iOS 10.3 or higher: Tap the Settings app to open it.

When you purchase a new iOS device, most iCloud options are on by default. Here's how to change them if you don't necessarily want to be cloud-connected for everything. The push towards cloud services ...

To fix contacts not showing up on your iPhone, try restarting your phone or showing all contacts. You can also try to sync your contacts with connected email accounts or your iCloud contacts.