Groups Fa ceTime (later) accept
If you are not the initiator of the call but group participants, then you receive a notification in the usual way. A tip on it establishes the connection. If you need a moment, you can join the conference later. To do this, open the appropriate group in the News app. Here you will be shown that a group discussion is in progress. A tip on "Join" will add you to the call.
Add More Attendees
In iOS 12, you'll need to decide who's going to join the group conversation. You may also notice in the process that a person is missing. You can add or invite these at any time. To do this, tap the symbol with the three dots. Below the usual call options, you will see the list of participants. At the bottom, you can add another person to the Plus icon or invite them to the group.
Previously, FaceTime was a standard video calling application. With iOS 12, Apple has not only expanded the functions to group calls, but now also allows effects. You will see a new star symbol at the bottom of the screen. Tap it and you will get different options. FaceTime uses stickers from the news app and allows iPhone-X users to use Animojis or Memojis. The stickers can be placed freely while the Animojis (and Memojis) serve as a mask for your face.