When an individual first attempts to join a private group, his or her membership will be listed as "pending." Once an administrator of the group upgrades their membership, they will be able to receive messages, and depending on if the group is moderated or not, send messages.
When someone first attempts to join a private group, their membership is listed as "pending." Once an administrator upgrades their membership, they can receive messages and, depending on whether the group is moderated or not, send messages.