For the income callings, you can answer it in the headset or speaker mode. If you always use speakerphone for everything, you can set the Speaker as accessibility setting. For you always have the headphone attached, it would be nice for you to choose Headset option so that it would not bother others when making a call. Now referring to the following operation, you can set Headset or Speaker as the call answer mode in your device.
Steps to set Headset or Speaker as call answer mode on iPhone:
Step 1: Enter Settings, click General and open Accessibility.
Step 2: Under PHYSICAL & MOTOR, choose Incoming Calls to move on.
