How to find my iPhone 12 Pro Max?

There isn’t enough detail to answer this question. You didn’t mention what happened to your iPhone, whether it was lost, stolen, or under some couch. If you have any other apple device, open the “Find My” app; Locate a device in Find My iPhone on iCloud.com - Apple Support (CA). If you don’t have/have access to any other apple device, visit https://www.icloud.com/find on the web (same way you were able to post here) and it will help you locate your iPhone. If you have the latest version of iOS installed, your phone will still be findable even if it is turned off.

Hello ~ Take a look here:

If your iPhone, iPad, or iPod touch is lost or stolen - Apple ...

~Katana-San~

We have no idea and can't tell you.

Apple does not track users devices.

If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support