I read that Find My will ping the last location of your device before the phone loses battery power. Is that true and if so, how do I find that information?

From:

Add your iPhone to Find My - Apple Support

• On a supported iPhone, turning on the Find My network allows you to locate your iPhone for up to 24 hours after it’s turned off, or up to 5 hours when it’s in power reserve mode.
• Send Last Location: If your device’s battery charge level becomes critically low, its location is sent to Apple automatically.

Read this article for how to use the Find My app to locate a device. I suspect hte last location information is kept in the same place.

Use the Find My app to locate a missing device or item - Apple Support