If you're the group admin, you can invite people to join a group simply by sharing a link with them. To share a group invite link:
Note: Any WhatsApp user you share an invite link with can join the group, so only use this feature with trusted individuals. It's possible for someone to forward the link to other people. If so, those other people can also join the group and the group admin won't be asked to approve those other people before they join.
If you exit a group, you'll be removed from the group. However, you'll still see the group in your Chats tab and be able to read the chat history. If you're the only group admin and you exit a group, a participant is chosen at random to become the new admin. To exit a group: