How to Turn On Additional Physical and Motor Settings on Your iPhone 6
You may want to adjust the physical and motor settings on your iPhone to meet your individual needs. Use these On/Off settings in the Accessibility settings to help you deal with how fast you click and how you answer phone calls:
Home-press Speed: Sometimes if you have dexterity challenges, it’s hard to double-press or triple-press the Home button fast enough to make an effect. Choose the Slow or Slowest option when you tap this setting to allow you a bit more time to make that second or third tap.
Call Audio Routing: If you prefer to use your speaker phone to receive incoming calls, or you typically use a headset with your phone that allows you to tap a button to receive a call, click this option and then choose Headset or Speaker. Speakers and headsets can both provide a better hearing experience for many.
If you have certain adaptive accessories that allow you to control devices with head gestures, you can use them to control your iPhone, highlighting features in sequence and then selecting one. Use the Switch Control feature in the Accessibility settings to turn this mode on and make settings.