Make and receive FaceTime audio calls on Mac
When you want to connect with someone without using your camera, you can make a FaceTime audio call. When you make a FaceTime audio call, you use your Mac’s Wi-Fi connection instead of your iPhone’s plan minutes.
Note: You can make a FaceTime audio call to anyone who has an Apple device that meets these requirements. To talk with others, you can make a phone call instead.
Make a FaceTime audio call
In the FaceTime app
on your Mac, click New FaceTime.In the New FaceTime window, enter the email address or phone number of the person you want to call. You may need to press Return.
Tip: If the person is in your Contacts, you can just enter their name or select them from Suggested. You can also add a contact from the New FaceTime window.
Click
and choose FaceTime Audio. The camera is automatically off when you start the call. To switch to a video call, click the video button 
.
Siri: Say something like: “FaceTime audio [phone number].” Learn how to use Siri
Answer a FaceTime audio call
When you’re signed in and FaceTime is turned on, you can accept calls even if FaceTime isn’t open. See FaceTime requirements.
On your Mac, do one of the following when a notification appears in the top-right corner of the screen:
Accept an incoming call: Click Accept.
Accept a video call as an audio call: Click
next to Accept, then choose Answer as Audio. When you’re in an audio call or a phone call, the camera is automatically off.Accept a call and end the current call: Click End & Accept.
Accept an audio call and put the current audio call on hold: Click Hold & Accept. When you end the new call, the call on hold resumes. You can pause one audio call at a time.
After you’re on a call, you can add more people.
Decline a FaceTime audio call
On your Mac, do one of the following when a notification appears in the top-right corner of the screen:
Decline a call: Click Decline.
The caller sees that you’re not available for a call.
Tip: If the call came from someone you don’t want to receive calls from, you can block the caller.
Decline a call and send a message using iMessage: Click
next to Decline, choose Reply with Message, type your message, then click Send. Both you and the caller must be signed in to iMessage.Decline a call and set a reminder to call back later: Click
next to Decline, then choose how long you want to wait to receive a reminder. When the time comes, you receive a notification — click it to view the reminder, then click the link in the reminder to start the call.
End a FaceTime audio call
To end an audio call, click the End button 
in the call notification.