How to find my iPhone's location?
Where is my phone location
[Re-Titled by Moderator]
iPhone 8 Plus
Question marked as
If you had Find My iPhone enabled on the phone, you may be able to track the phone (or its last known location) from one of your other Apple devices, or from a Web browser.
You can also mark the phone as Lost to remotely lock it. (Just be sure not to lose the pass code that you set up when you mark the phone as Lost. You don't want to lock yourself out.)
Use the Find My app to locate a missing device or item - Apple Support
If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support
If you're asking how to enable Find My, in case your iPhone gets lost in the future, see:
Set up Find My on your iPhone, iPad, iPod touch, or Mac - Apple Support