iPhone 12 Pro Max camera is not working

First, try a forced restart. If that doesn't work take it in to the Apple store to have it looked at.

• Press and quickly release the volume up button

• Press and quickly release the volume down button

• Press and hold the side button.

• When the Apple logo appears, release the button.

Force restart iPhone - Apple Support (IN)

Make an appointment at the Genius Bar to have it diagnosed.

Genius Bar Reservation and Apple Support Options - Apple

Hello~ Try clicking on the link below and working thr the information found there…

If the camera or flash on your iPhone, iPad, or iPod touch isn't working - Apple Support

~Katana-San~

What’s it doing or not doing? If you don’t provide any details, how are we to know what’s going on and suggest possible solutions?