Invite a friend as a member
Inside the room, choose Invite and invite your friend. They receive a room card in your direct message with Accept and Decline. Accepting makes them a member, so they can help decorate and usually return without knocking.
Share a room link
Copy the room link from Invite and send it to someone. A link lets a new visitor ask to join by knocking; it does not automatically make them a member.
Unanswered invitations
The owner and admins can see pending invitations in Room Settings → Members and cancel them. A member invitation expires after seven days; send a new one if needed.
For a planned get-together, try creating an event instead.