This article explains how to play music via Bluetooth on iPhones running iOS 16 through iOS 12.

Playing music from your iPhone to a Bluetooth device consists of three steps: turn on Bluetooth on both devices, pair the devices, and start streaming music.

Turn on Bluetooth on your iPhone, if it isn’t already turned on. Go to Settings > Bluetooth and tap the On/Off slider to turn it on, or open the Control Center and tap the Bluetooth icon to turn it on.

Enable pairing mode on the Bluetooth device. Select the Pair button or enable a setting via a companion app.