Warranty
How do I use my warranty for my iPhone 14promax that I got less then a year ago but the back cracked o me idk how cause it was in the case
iPhone 14 Pro Max, iOS 16
You should contact the official Apple Support about that and ask them how to proceed.
Contact Apple for support and service - Apple Support
Damages caused by accident are not covered by the One-Year Apple warranty:
Legal - iOS Warranty Document Us - Apple