How to check if an iPhone is original?
How do I know if my iPhone is original
[Re-Titled by Moderator]
iPhone 14 Pro Max, iOS 16
See if it appears under warranty information:
Check Your Service and Support Coverage - Apple Support
or:
Settings > General > About ( if using iOS 12.2+)
The only real way to be certain a device is not "fake" is to only buy one from Apple or an Apple Authorized dealer.