How do I pair hbs700 with iphone 6

As far as I know, the HBS700 does not have a mute function on the headset. The manual is available from the LG product support site: http://www.lg.com/us/support-mobile/lg-HBS700 . The direct link is http://www.lg.com/us/support/products/documents/HBS700_Manual.pdf . Oddly, the microphone does get muted automatically if your device is connecting to a local wi-fi signal.

I wish that I had better news for you.

Cindy Wells

Turn the bluetooth radio off on your old phone. Turn on the hbs700. Your earpiece should automatically go into pairing mode when it does not detect your old phone. Turn on the bluetooth radio on your new phone and search for your hbs700. Connect to and you're done.

Iphone maybe korean ...

It sounds like you may have a broken wire inside. I would inspect the circuit board on the left side of the earpiece first. Look for shorts, broken wires or anything that looks burnt. You can use a multi meter to make sure the wires in the neck band are not broken. Here is the video showing how to open it up:
LG Tone HBS700 730 repair mod and upgrade

Here is a how to video to open up the earpiece and replace the battery if needed. While you have the earpiece open you can check the the battery with a volt meter to see if it's holding a charge. The stock battery for this earpiece is 3.7v and 195mAh.
LG Tone HBS700 730 repair mod and upgrade

The LG HBS 700 will automatically go into pairing mode if it does not detect the last device it was paired with. So, make sure all other bluetooth devices are off, turn the earpiece on and wait for the status light to show solid blue. Then you can turn on the bluetooth on your other device and search for the HBS 700.

You may need to replace the earbuds. They tend to go bad after a while. Here is a link on how to replace them. It's not hard at all.
LG Tone HBS700 730 repair mod and upgrade

This might help

Call lg parts section but I am sure it will be the whole unit that you will be replacing.