[1][2] Apple offers a free service called Find My for iPhones running iOS.
Similarly, Google offers Find My Device for phones running Android.
[3] Some of these applications may have limitations which can be checked before installing, such as only working in some countries, dependencies upon the phone's implementation of GPS, etc.
Computers rarely have built-in GPS receivers or mobile telephone network connectivity, so these methods of location and signalling are not available.
However, a WiFi-connected computer (typically a laptop computer) can find its approximate location by checking WiFi networks in range against a database, allowing approximate location to be determined and signalled over the Internet.