You can also make a phone call to anyone right from your Mac, using the cellular connection of your nearby iPhone. See set up to make phone calls on your Mac, you can choose whether to make a FaceTime audio call or a phone call. When you’re on a FaceTime audio call or phone call, the camera is automatically off.
Each participant appears in a tile on the screen. When a participant speaks or you click a tile, that tile moves to the front and becomes more prominent. Tiles that can’t fit on the screen appear in a row at the bottom of the screen. To find a participant you don’t see, scroll through the row.
Tip: If you don’t want the tile of the person speaking to become larger, you can deselect the option in FaceTime preferences. Choose FaceTime > Preferences, click Settings, then deselect Speaking under Automatic Prominence.
To send an audible alert to a caller who hasn’t yet joined the call, click the Sidebar button change your view of the call, Change FaceTime ringtones on MacApple Support article: If FaceTime isn’t working on your Mac