There are three ways someone can join a group:
1. By invitation
A group administrator can invite people to join their group. This is in the form of a link that can be sent to a potential member. By logging in, they can see the group they've been invited to. To accept the invitation, they must join the group.
If they choose not to join the group, their invitation remains pending.
2. Added by administrator
A group administrator can add people to their group. The admin chooses whether to send a welcome email which notifies the people that they are now part of a group.
Upon logging in, the user can see the group they're now a member of.
3. Discover and join
An organization has a directory of groups that users can join. Some groups are hidden (only existing members know that the group even exists: it's not visible to anyone else), some are visible within the organization (only visible to a user if they are already a member of a group within the organization), and some are visible to the world (visible even if a user isn't logged in).
People can join groups they can see, providing the group membership isn't by invitation only.
Where a group's membership is moderated, users can request to join and must wait until a group admin or moderator approves their membership request. If a group's membership isn't moderated, people can join for themselves.
Find groups to join on the Groups page.
There are two ways to leave a group:
1. Group member leaves
A member can remove themselves from a group at any time. Go to the Groups page and select which group(s) to leave.
2. Removed by a group administrator
A member can be removed by a group administrator (or organization owner) using the group Add/Remove member tool. The group admin can optionally choose whether to also send a "Goodbye" system message to the member, notifying them that they have been removed.