Does anyone know how to track a stolen iPhone?

I went on a hike one day about 2 1/2 weeks ago and I lost my iPhone 12 pro max and then I kept looking for and I couldn’t find it so I gave up and then I get notifications on Facebook saying that a iPhone 12 Pro Max was using my Facebook account a week ago. Is there any way that anybody could help me I would greatly appreciate it.

Unfortunately, no-one here is going to be able to help you - I would suggest talking to Apple and Facebook (about your account details at each place) and your insurer (if any).