How can I make audio calls using face time with iOS 12.1.1 ?

Greetings Mkamelgafi,

Thanks for visiting the Apple Support Communities! I understand you're curious how to make a FaceTime audio call with your iPhone.

The following support article provides helpful information for using FaceTime on an iOS device: Use FaceTime with your iPhone, iPad, or iPod touch

Specifically, the following section will show you how to make a FaceTime audio call:

Make a FaceTime call 

To make a FaceTime call, you need the person's phone number or registered email address. There are a few ways to make a FaceTime call:

In the FaceTime app, tap  and type the person's phone number or email address. Tap the number or address, then tap Audio  or Video .

If you have the person's phone number or email address saved in your Contacts, you can begin typing their name and tap the name when it appears. Then tap Audio  or Video . 

You can also begin a FaceTime video call from your iPhone during a phone call. Tap the FaceTime icon in the Phone app to switch to FaceTime.

Cheers!