To answer a call, select Accept. To decline a call and send it directly to voicemail, select Decline.
Note: If iPhone is locked while receiving a call, select and drag the Phone icon to the right to answer the call or press the Sleep/Wake button twice to decline the call. In some areas, declined calls are disconnected without being sent to voicemail.
To decline a call with a text message, select Message, then select the desired message.
Note: To create a custom reply, select Custom, enter the Desired message then select the Send icon.
To make a call, from the home screen select the Phone app.