How can I find my lost iPhone 12?

I'm sorry you lost your phone, but Apple doesn't get involved in lost or stolen devices, so Apple can't help you.

See what you can do to find a lost phone here --> Find your lost iPhone or iPad - Apple Support

This presumes your phone is powered on, connected to a network and most IMPORTANTLY, Find My was enabled before the phone went missing.

And if the iPhone was stolen, you may get calls or texts claiming to be from “Apple” or from the local “police”, claiming to have found your iPhone, and requiring you to authenticate your ownership by providing your Apple Account credentials.

Those calls and texts are from the thieves, and you do not want to provide your credentials.

Providing your credentials will only make a bad problem worse.

What to do: If your iPhone or iPad was stolen - Apple Support