Q: My iPhone 6 ran out of charge and unable to charge it on iMac or wall socket.

Leave it connected to the wall for 30 minutes, try to avoid fully discharging it in future

Try this. Plug the phone into a wall socket with a known good adapter and cable. Let it sit for about 15 minutes. Then, press and hold the Home and power buttons for about 12 seconds. If the Apple appears, let go and allow to continue booting. If no Apple appears, make an appointment at the Genius Bar at your local Apple Store.

In addition to what Csound1 & Meg St._Clair said, this article might help:

If your iPhone, iPad, or iPod touch won't charge - Apple Support

Try the simple things first, like a different lightning cable or inspect the lightning port.  If you can't or feel uncomfortable doing that I'm sure the Geniuses at an Apple Store will help.