How do you use call waiting on iPhone 6?

To use call waiting on an iphone 6, first ensure that it's enabled in your settings. Go to Settings > Phone and check that Call Waiting is turned on. When you're on a call and receive a second call, you'll hear a beep indicating the incoming call. You can then tap Hold & Accept to put the first call on hold and answer the second call, or tap End & Accept to end the first call and answer the new one.