Make a phone call using Messages on Mac
You can make a phone call from your Mac using Messages if you have an iPhone with iOS 8 or later nearby. Calls are relayed through your iPhone, but you use your Mac microphone and speakers to communicate. Phone calls use mobile minutes. Mobile charges may apply. See FaceTime phone call requirements.
In the Messages app
on your Mac, in the top-right corner of a conversation, click the Details button 
, then click the Call button 
.To search for contacts and content in conversations, click in the Search field in the top-left corner and enter what you’re looking for. Or choose from the suggested contacts, links, photos and more.
You can’t call someone who’s restricted by communication limits in Screen Time.
If there’s more than one number in the contact card, choose the number to call. If there’s only one number, the call starts immediately.