If you have an iPhone, a recent update to the app Find My, allows you to find traces of the lost phone even if its battery is completely exhausted. Applies to iPhone 11, 12 and 13 with iOS 15 and all you have to do is check settings. See how:
1. You go to Settings > [your name]> Find My. If you have to sign in, you enter your Apple ID.
2. Keyboards Find My iPhone and then drag to the right to activate it, (although it can be activated automatically).
3. Alternatively, you can enable Find My network. If you are not connected to the internet, the application Find My can find the location using Find My network. On iphone with iOS 15, Find My network allows you to find the location of the device up to 24 hours after it is turned off. If the battery is extremely low, the location will be automatically sent to Apple.
What applies to Android
The Find My Device Automatically activates when you add a Google Account to any Android device. For it to work, just follow the steps below:
1. Sign in to a Google Account
2. Connect to the internet (Wi-Fi or data)
3. Activate the Location setting
4. Activate Find My Device
If your phone is already lost, it's too late to do the above steps so you can do the process as early as possible.