How to Find My iPhone when it's off?
My wife lost her iPhone somewhere in our house but it’s now dead and we can’t seem to find it anywhere how do we get it to make a noise
[Re-Titled by Moderator]
iPhone 15 Plus
My wife lost her iPhone somewhere in our house but it’s now dead and we can’t seem to find it anywhere how do we get it to make a noise
[Re-Titled by Moderator]
iPhone 15 Plus
Switched Off? Still traceable: Even if the iPhone is switched off it is findable, see the pic below.

iPhone is findable even when powered off. (iOS 15 and above)
Did you enable Find My network? See the pic below
If yes, read below how it may get located.
The Find My network is an encrypted, anonymous network of hundreds of millions of Apple devices that can help you locate your device.
From the above, I infer that when another device comes in close proximity to your powered-off device the GPS/Bluetooth from both devices will form a network and your device's location info will be displayed to you on your device only. As long as both devices are/have...
Set up Find My on your iPhone, iPad, iPod touch, or Mac
Switched Off? Still traceable
Even if the iPhone is switched off it is findable, see the pic below.

Device Offline?
I see my device in Find My, but it's offline

If you see "Offline," "No location available," or "Location Services Off," your device might be offline for one of these reasons:
Don't see your device?
Don'ts
If the device is removed from an account after it is erased, Activation Lock will be turned off. This allows another person to turn on and use the device.
An example of my iPhone 5 is given in the GIF below. There is no "Undo" after you remove it from your account.
How to Find My iPhone when it's off?