How can group chat enliven the atmosphere?

This depends on the user's attributes in the group:

If you are all family members, you may wish to talk about health topics, ask the health status of the elderly and praise the children of relatives, so that the topic will be relaxed at once;

Colleagues and friends can try to send out some small red envelopes, or join a group to eat, sing and entertain. You can also speak as an organizer or proposer to make the atmosphere more active.