Make calls in FaceTime on Mac
Make a FaceTime call to one or more people (up to 32) who have a Mac or an iOS device with the FaceTime app and are connected to the Internet. FaceTime calls use Wi-Fi or mobile data.
For information about system requirements for using FaceTime, see FaceTime requirements.
Ask Siri. Say something like: “FaceTime mum.” Learn more about Siri.
You can also make a phone call to anyone right from your Mac, using the mobile network connection of your nearby iPhone. See Make and receive phone calls in FaceTime.
In the FaceTime app
on your Mac, sign in to FaceTime and have it turned on.In the field at the top of the FaceTime window, enter the email address or phone number of the person you want to call. You may need to press Return.
If you have a card for the person in the Contacts app, you can just enter the person’s name. For information about adding contacts, see Add contacts while using FaceTime.
To make a call with multiple people (Group FaceTime), repeat step 2 until all participants are listed.
Note: Group FaceTime is available with the macOS Mojave 10.14.3 Supplemental Update or later, or iOS 12.1.4 or later. This feature may not be available in all regions. See the Apple Support article About the security content of macOS Mojave 10.14.3 Supplemental Update.
To start the FaceTime call, click the Video button
or the Audio button 
(or use the Touch Bar).If you click the Audio button
and you’re set up to make phone calls on your Mac, you can choose whether to make a FaceTime audio call or a phone call.
If you make a video call that’s declined or unanswered, you can click Message to send the person an iMessage (both of you must be signed in to iMessage).
Once you’re on a call with one or more people, you can do any of the following: