One way to track a cell phone's location is to install a security suite that can provide the phone's location on demand. These programs use the phone's built-in GPS capabilities, or they can provide data using cell tower pings and Wi-Fi network logins.
There are a wide variety of cell phone tracking programs available. Most cell phone service providers have their own technology for tracking cell phones, as do the manufacturers of the major operating systems. Android, iOS and Windows all have tracking features built into the operating system, and there are many third-party apps that provide this service such as Prey. Most of these require the user to activate the service on the phone prior to tracking.
If a phone is lost without tracking software, there may still be some options available to locate it. If the phone is connected to a Google account and has location-based services turned on, the Google Maps service offers a location history feature for all connected devices. This is not as accurate as a GPS locator, but it can provide a reasonable estimate of the phone's last known position.
Cell phone tracking software should only be used with the permission of the phone's owner. Using this technology on someone's phone without their permission may be a crime, punishable by a jail sentence in some states.