ios: Add new password to iCloud Keychain

I'm trying to add username/password to user's iCloud Keychain from my app so they don't have to do it manually. The problem is I don't see any way to do that.

https://developer.apple.com/documentation/security/keychain_services/keychain_items/adding_a_password_to_the_keychain

That tutorial seems to add the password to an "invisible" keychain. I guess it only to store password locally in a secured manner. When I run the code, there is no error. If I try to add the same username, it return errSecDuplicateItem which suggests that the previous one was successfully added. But I don't see the new entry in my iCloud Keychain

Does iOS support adding iCloud Keychain directly within an app?

Thanks