How do I track my stolen phone when switched off

No. If the phone can’t send a signal how could it possibly be tracked? If anyone ever tries to use it you will be able to track it, so the fact that you can’t means that no one is using it. Be aware, however, if you receive a message from “Apple” saying your phone has been found, with a link to view its location. That will be a phishing message so the thief can get your Apple ID to remove activation lock; Apple never sends any such message.

And if you could locate it, what would you do? Confront the thief? People have been murdered doing that.

The phone must be turned on and connected to the internet in order to send a location signal. Check the link in blue above your name on this page for further info.

I have waited for the phone to be turned on or connected to the internet

Yet to no avail ,so is there any other way to locate my stolen iPhone