Put your JBL headphones in pairing mode:
There is a key of power, hold down it and at the same time press the key of the LED light will be blue (normally for 5 seconds). This indicates pairing mode.
Scroll down to the list of options in your iPhone’s Bluetooth & Devices where you should be able to see your JBL headphones. Tap on it to pair.

Read More : https://techyvibe.net/how-to-pair-jbl-earbuds/