12 Pro Max

If you have either dropped the device accidentally or exposed it to liquid or used it beyond acceptable temperature limits then…

Take your device to an Apple Retail Store or Apple Authorized Service Provider, or contact Apple Support:

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falisha100 wrote:

my iPhone 12 Pro Max overheated

I am not aware of the ambient temperature in which you are using the iPhone. However --> Keeping iPhone, iPad, and iPod touch within acceptable ...

Store the device where the temperature is between -20º and 45º C (-4º to 113º F). Don’t leave the device in your car, because temperatures in parked cars can exceed this range.

Use iOS devices where the ambient temperature is between 0º and 35º C (32º to 95º F). Low- or high-temperature conditions might cause the device to change its behavior to regulate its temperature. Using an iOS device in very cold conditions outside of its operating range might temporarily shorten battery life and could cause the device to turn off. Battery life will return to normal when you bring the device back to higher ambient temperatures. Using an iOS device in very hot conditions can permanently shorten battery life.

Without knowing what Apple Care plan you have in place it is difficult to comment.