stolen iPhone
What do I do when my iPhone is stolen, and its offline on find my iPhone
iPhone XS Max, iOS 12
Question marked as
What if your device is off or offline?
If your missing device is off or offline, you can still put it in Lost Mode, lock it, or remotely erase it. The next time your device is online, these actions will take effect. If you remove the device from your account while it's offline, any pending actions for the device are canceled.
If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support