QUOTE(squall8985 @ Feb 6 2017, 02:15 PM)
What if i have two iPhone both using same icloud ID?
OR
Two iPhone both using different icloud ID?
IIRC apple allows association of not more than 5 devices per apple id.
and the system follows the apple id. I myself uses 2 apple ids for my phone for the simple reason that 1 account is Malaysian and the other US account. Both have pros and cons. My main account and apps all from Apple US. So far no issues with the different iclouds as both have the same data, and my icloud only backup phone settings, notes, contact lists and calendar.
For the former scenario, both phones will be sync with the latest data in iCloud.
My main backup would be with iTunes. FYI always use encrypted backup which differs from the non-encrypted. Encrypted backup will also save all password settings.