

When you receive a phone call, the Incoming call screen shows the caller ID. If you miss a call, you'll see in the status bar.
To answer an incoming call:

During a call, you can use the keypad to enter numbers or codes, use speakerphone or a paired Bluetooth device, and add other people to the call.
Tip : You can save a recent call as a contact.
Auto answer on headset
 
Not all carriers support this feature. 
You can set your phone to automatically answer calls after 2, 5, or 10 seconds when you're using a headset (wired or Bluetooth).
 .
. > Settings .
> Settings .Dismiss incoming call
If you don’t want to talk to the caller, you can:

 .
. and enter a number.
and enter a number. .
. to call the number.
to call the number. .
.You can place calls from:
 Phone app
Phone app Contacts app
Contacts app Assistant app
Assistant app
Return a recent call
In the  Phone app, touch
Phone app, touch  , then touch
, then touch  next to the number.
next to the number.
Dial a  favourite contact
favourite contact 
In the  Phone app, touch
Phone app, touch  to see your favourites, then touch the contact.
to see your favourites, then touch the contact.
In the  Contacts app, at the top of the list under
Contacts app, at the top of the list under  , touch the contact.
, touch the contact.

Dial by contact lookup
 Phone app and touch
Phone app and touch  .
.  Contacts app.
Contacts app. search field, start typing the name to select from matches.
search field, start typing the name to select from matches. next to the number to call.
next to the number to call.Change default calling app
You can download additional calling apps from Play Store. After you've installed one, you can make it your default calling app.
Adjust sound during call
While listening, you can:
 .
. to use or stop using the device.
to use or stop using the device. . You can hear the caller but they can’t hear you.
. You can hear the caller but they can’t hear you.Enter a number during call

Touch on the call screen to use the numeric keypad.
Use other apps during call
When you hold your phone to your ear, the screen goes dark to avoid accidental touches. To wake it up, move it away from your ear or press the Power button.
To hide the call and use other apps, swipe up from the bottom of the screen.
To return to the call, swipe the status bar down and touch Ongoing call
Answer call waiting
If call waiting is active and a new call comes in, you can answer it. Touch Hold and Answer Voice . The first call is put on hold.

To switch between calls, touch

To merge the calls, touch
Record calls to start and
to start and  to stop.
to stop. Phone app, touch
Phone app, touch  .
. means the call was recorded. Touch the call.
means the call was recorded. Touch the call. to play the recording.
to play the recording. to share it.
to share it.Recording a conversation without the consent of the other party is illegal in most countries. Know your country's laws before recording a call.

Touch on the call screen.
Or, swipe down from the top of any other screen to view the call notification and touch Hang up