There are several differences between group chats and multi-person chats.
Group chats
Group chats let you set a group name and profile photo, as well as use convenient features like Albums and Notes.
However, the friends you invite need to tap the Join button to participate in the group.
To start a group chat:
1. Go to the Home/Friends tab.
2. From Groups, select the group name and tap Chat.
Note: For the steps to create a group, see here.
Multi-person chats
With multi-person chats, you can start chatting with multiple friends right after being invited.
Compared to groups, the features you can use are limited, but multi-person chats offer the advantage of letting you easily create chats with multiple friends.
To start a multi-person chat:
1. On the Chats tab, tap the speech bubble icon at the top right of the screen.
2. Tap Chat.
3. Choose the friends you want to chat with, then tap Create.