1. From the home screen, select the  Phone app.
2. Select the Keypad tab, then dial the desired number. Select the Call icon.
When you have an incoming call, select the Decline icon to decline the call. Select the Accept icon to accept the call.
Note: If your iPhone is locked, select and drag the  Phone icon to the right to answer a call. To decline a call from the lock screen, press the Side button twice.
Select the Call window, then select the Message icon. Select the desired message.
Note: To create a custom reply, select Custom.... Enter the desired message, then select the  Send icon.